Fiber-reinforced thermoplastic resin molded article, and fiber-reinforced thermoplastic resin molding material

ABSTRACT

A fiber reinforced thermoplastic resin molded article includes 5 to 45 parts by weight of carbon fibers (A), 1 to 45 parts by weight of organic fibers (B), and 10 to 94 parts by weight of a thermoplastic resin (C), based on 100 parts by weight of the total amount of the carbon fibers (A), the organic fibers (B), and the thermoplastic resin (C). The carbon fibers (A) in the fiber reinforced thermoplastic resin molded article have an average fiber length (L A ) of 0.3 to 3 mm. The organic fibers (B) in the fiber reinforced thermoplastic resin molded article have an average fiber length (L B ) of 0.5 to 5 mm, and a number average fiber diameter (d B ) of 35 to 300 μm. The fiber reinforced thermoplastic resin molded article is excellent in impact strength and surface appearance.

TECHNICAL FIELD

This disclosure relates to a fiber reinforced thermoplastic resin moldedarticle comprising carbon fibers and organic fibers, and a fiberreinforced thermoplastic resin molding material.

BACKGROUND

Molded articles comprising reinforcement fibers and a thermoplasticresin are lightweight and have excellent mechanical properties, and thushave been widely used, for example, in sports applications, aerospaceapplications, and general industrial applications. Examples of suchreinforcement fibers include metal fibers such as aluminum fibers andstainless fibers, inorganic fibers such as silicon carbide fibers andcarbon fibers, organic fibers such as aramid fibers and poly p-phenylenebenzoxazole (PBO) fibers, and the like. Among these, carbon fibers aresuitable in terms of the balance between specific strength, specificrigidity and lightness; and in particular, polyacrylonitrile-basedcarbon fibers are suitably used.

The mechanical properties of a carbon fiber reinforced thermoplasticresin molded article can be enhanced, for example, by increasing thecontent of carbon fibers, but an increased content of carbon fiberstends to result in uneven distribution of the carbon fibers in thecarbon fiber reinforced thermoplastic resin molded article, oftencausing a reduction in impact strength. Thus, alternatively, themechanical properties of a carbon fiber reinforced thermoplastic resinmolded article can be enhanced, for example, by adding organic fibershaving flexibility and high elongation at break in addition to thecarbon fibers.

As a long-fiber reinforced composite resin composition having a highmechanical strength and provided with conductivity, a long-fiberreinforced composite resin composition comprising an olefin resin,organic long fibers, and carbon fibers is disclosed (see, for example,JP 2009-114332 A). Further, as a fiber reinforced plastic excellent inimpact resistance, a fiber reinforced plastic composed of reinforcementfibers and a thermoplastic resin is proposed, wherein the reinforcementfibers are composed of carbon fibers and heat-resistant organic fibers(see, for example, JP 2014-62143 A). In addition, as a fiber reinforcedthermoplastic resin molded article excellent in impact strength andlow-temperature impact strength, a fiber reinforced thermoplastic resinmolded article including carbon fibers, organic fibers and athermoplastic resin is proposed, wherein the carbon fibers and theorganic fibers each have an average fiber length within a specificrange, and the average straight-line distance between two edges of asingle fiber and the average fiber length of the carbon fibers and theorganic fibers are in a specific relationship (see, for example, WO2014/098103).

However, a molded article obtained using the technique disclosed in JP2009-114332 A or JP 2014-62143 A has an improved impact strength but yethas a problem of deteriorating a surface appearance of molded article byadding organic fibers. Further, although the technique disclosed in WO2014/098103 permits production of a molded article with a significantlyimproved impact strength and an improved surface appearance by adjustingfiber length to the specific range. However, a further improvement insurface appearance along with maintaining impact strength of members andparts is expected with expanding various applications in recent years.

It could therefore be helpful to provide a fiber reinforcedthermoplastic resin molded article excellent in impact strength andsurface appearance.

SUMMARY

We thus provide:

A fiber reinforced thermoplastic resin molded article, comprising: 5 to45 parts by weight of carbon fibers (A); 1 to 45 parts by weight oforganic fibers (B); and 10 to 94 parts by weight of a thermoplasticresin (C), based on 100 parts by weight of the total amount of thecarbon fibers (A), the organic fibers (B), and the thermoplastic resin(C),

wherein the carbon fibers (A) in the fiber reinforced thermoplasticresin molded article have an average fiber length (L_(A)) of 0.3 to 3mm, and

wherein the organic fibers (B) in the fiber reinforced thermoplasticresin molded article have an average fiber length (L_(B)) of 0.5 to 5mm, and a number average fiber diameter (d_(B)) of 35 to 300 μm.

Further, the fiber reinforced thermoplastic resin molding material haseither of the following constructions:

A fiber reinforced thermoplastic resin molding material, comprising: 5to 45 parts by weight of carbon fibers (A), 1 to 45 parts by weight oforganic fibers (B), 10 to 94 parts by weight of a thermoplastic resin(C), and 1 to 25 parts by weight of a compound (D) having a meltviscosity at 200° C. that is lower than that of the thermoplastic resin(C), based on 100 parts by weight of the total amount of the carbonfibers (A), the organic fibers (B), and the thermoplastic resin (C),wherein:

the organic fibers (B) have a number average fiber diameter (d_(B)) of35 to 300 μm;

the thermoplastic resin (C) is contained at the outer side of acomposite (F) obtained by impregnating a fiber bundle (E) comprising thecarbon fibers (A) and the organic fibers (B) with the compound (D);

the carbon fibers (A) and the organic fibers (B) are unevenlydistributed in a cross section of the fiber bundle (E); and

the length of the fiber bundle (E) and the length of the fiberreinforced thermoplastic resin molding material are substantially thesame.

A fiber reinforced thermoplastic resin molding material, comprising:

a carbon fiber reinforced thermoplastic resin molding material (X)comprising 5 to 45 parts by weight of carbon fibers (A), 35 to 94 partsby weight of a thermoplastic resin (C), and 1 to 25 parts by weight of acompound (D) having a melt viscosity at 200° C. that is lower than thatof the thermoplastic resin (C), based on 100 parts by weight of thetotal amount of the carbon fibers (A), the thermoplastic resin (C), andthe compound (D) having a melt viscosity at 200° C. that is lower thanthat of the thermoplastic resin (C), wherein the thermoplastic resin (C)is contained at the outer side of a composite (G) obtained byimpregnating the carbon fibers (A) with the compound (D), and the lengthof the carbon fibers (A) and the length of the carbon fiber reinforcedthermoplastic resin molding material are substantially the same; and

an organic fiber reinforced thermoplastic resin molding material (Y)comprising 1 to 45 parts by weight of organic fibers (B), 35 to 94 partsby weight of a thermoplastic resin (H), and 1 to 25 parts by weight of acompound (I) having a melt viscosity at 200° C. that is lower than thatof the thermoplastic resin (H), based on 100 parts by weight of thetotal amount of the organic fibers (B), the thermoplastic resin (H), andthe compound (I) having a melt viscosity at 200° C. that is lower thanthat of the thermoplastic resin (H), wherein the organic fibers (B) havea number average fiber diameter (d_(B)) of 35 to 300 μm.

The fiber reinforced thermoplastic resin molded article provides a highreinforcing effect and has an excellent impact strength and a surfaceappearance. The fiber reinforced thermoplastic resin molded article isextremely useful for electrical and electronic equipment, officeautomation equipment, household electrical appliances, housings,automotive parts and the like.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view illustrating a molding material cross sectionin an example where the carbon fibers (A) envelop the organic fibers (B)in a cross section of the fiber bundle (E).

FIG. 2 is a schematic view illustrating a molding material cross sectionin an example where the organic fibers (B) envelop the carbon fibers (A)in a cross section of the fiber bundle (E).

FIG. 3 is a schematic view illustrating a molding material cross sectionin an example where a bundle of the carbon fibers (A) and a bundle ofthe organic fibers (B) are present separated by a certain boundary in across section of the fiber bundle (E).

FIG. 4 is a schematic view illustrating the fiber diameter of the carbonfibers (A) or the organic fibers (B).

DESCRIPTION OF SYMBOLS

1: Carbon fiber

2: Organic fiber

3: Thermoplastic resin

4: Fiber contour A

5: Fiber contour A′ opposite to fiber contour A

6: Shortest distance

DETAILED DESCRIPTION

The fiber reinforced thermoplastic resin molded article (hereinafter,sometimes referred to as “molded article”) comprises at least carbonfibers (A), organic fibers (B), and a thermoplastic resin (C). It ispreferred that the molded article further comprises a compound (D)having a melt viscosity at 200° C. that is lower than that of thethermoplastic resin (C).

The carbon fibers (A) are in the form of a continuous reinforcementfiber filament, and serve as a reinforcement material to provide themolded article with high mechanical properties. The organic fibers (B)are also in the form of a continuous reinforcement fiber filament, andhave flexibility. The organic fibers (B), due to their flexibility, areless likely to break during molding, and likely to be present in acurved form in the molded article while keeping their long fiber length.Thus, the use of a fiber bundle (E) including the organic fibers (B) asa reinforcement material allows for providing a high impact strength tothe resulting molded article, as compared to using a fiber bundleconsisting of the carbon fibers (A), which are rigid and brittle andthus less prone to entanglement but susceptible to breakage. Thethermoplastic resin (C), which is a matrix resin having a relativelyhigh viscosity and excellent physical properties such as toughness,firmly holds the carbon fibers (A) and the organic fibers (B) in themolded article.

The molded article contains the carbon fibers (A) in an amount of 5 to45 parts by weight (5 parts by weight or more and 45 parts by weight orless), based on 100 parts by weight of the total amount of the carbonfibers (A), the organic fibers (B), and the thermoplastic resin (C).When the content of the carbon fibers (A) is less than 5 parts byweight, the molded article will have reduced flexural properties andimpact strength. The content of the carbon fibers (A) is preferably 10parts by weight or more. When the content of the carbon fibers (A) ismore than 45 parts by weight, on the other hand, the dispersibility ofthe carbon fibers (A) in the molded article will be reduced, oftencausing a reduction in the impact strength and a poor surface appearanceof the resulting molded article. The content of the carbon fibers (A) ispreferably 30 parts by weight or less.

Examples of the type of the carbon fibers (A) include, but are notlimited to, PAN-based carbon fibers, pitch-based carbon fibers,cellulose-based carbon fibers, vapor-grown carbon fibers, andgraphitized fibers thereof. The PAN-based carbon fibers are carbonfibers made from polyacrylonitrile fibers. The pitch-based carbon fibersare carbon fibers made from petroleum tar or petroleum pitch. Thecellulose-based carbon fibers are carbon fibers made from materials suchas viscose rayon and cellulose acetate. The vapor-grown carbon fibersare carbon fibers made from materials such as hydrocarbon. Among these,the PAN-based carbon fibers are preferred in terms of excellent balancebetween strength and elastic modulus. To provide conductivity, carbonfibers coated with a metal such as nickel, copper, or ytterbium can alsobe used.

The carbon fibers (A) preferably have a surface oxygen concentrationratio [O/C], which is the ratio of oxygen atoms (O) to carbon atoms (C)on the fiber surface as measured by X-ray photoelectron spectroscopy, of0.05 to 0.5. When the surface oxygen concentration ratio is 0.05 ormore, a sufficient amount of functional groups can be secured on thecarbon fiber surface to provide stronger adhesion, thereby furtherimproving flexural strength and tensile strength. The surface oxygenconcentration ratio is more preferably 0.08 or more, and still morepreferably 0.1 or more. The upper limit of the surface oxygenconcentration ratio is not particularly limited. In general, the upperlimit is preferably 0.5 or less, in terms of the balance betweenhandleability and productivity of the carbon fibers. The surface oxygenconcentration ratio is more preferably 0.4 or less, and still morepreferably 0.3 or less.

The surface oxygen concentration ratio of the carbon fibers (A) isdetermined by X-ray photoelectron spectroscopy according to thefollowing procedure. First, when a sizing agent and the like aredeposited on the surface of the carbon fibers, the sizing agent and thelike deposited on the carbon fiber surface are removed with a solvent. Abundle of carbon fibers is cut into a length of 20 mm, and the carbonfibers are spread on a sample support made of copper to be used asmeasurement samples. The measurement samples are set in a sample chamberof an X-ray photoelectron spectroscopy apparatus, and the measurement iscarried out while maintaining the interior of the sample chamber at1×10⁻⁸ Torr and using AlKα1, 2 as an X-ray source. As a correction valueof a peak associated with electrification during the measurement, thekinetic energy value (K.E.) of the main peak of C_(1s) is set at 1,202eV. The C_(1s) peak area is determined by drawing a straight baseline inthe K.E. range of 1,191 to 1,205 eV. The O_(1s) peak area is determinedby drawing a straight baseline in the K.E. range of 947 to 959 eV.

The surface oxygen concentration ratio is calculated as a ratio of thenumber of atoms, from the ratio of the O_(1s) peak area to the C_(1s)peak area, using an apparatus-specific sensitivity correction value.When an X-ray photoelectron spectroscopy apparatus model ES-200manufactured by Kokusai Denki Co., Ltd. is used, the sensitivitycorrection value is set at 1.74.

Examples of means of adjusting the surface oxygen concentration ratio[O/C] to 0.05 to 0.5 include, but are not particularly limited to,treatments such as electrolytic oxidation, chemical oxidation, and gasphase oxidation, among which electrolytic oxidation is preferred.

When the carbon fibers (A) are formed into a reinforcement fiberfilament, the number of single fibers in the filament is preferably, butnot particularly limited to, 100 to 350,000, and more preferably 20,000to 100,000 from the standpoint of productivity.

To improve the adhesion between the carbon fibers (A) and thethermoplastic resin (C) as a matrix resin, and the like, the carbonfibers (A) may be subjected to a surface treatment. Examples of thesurface treatment include electrolytic treatment, ozonation treatment,and UV treatment.

To prevent fluffing of the carbon fibers (A) or improve the adhesionbetween the carbon fibers (A) and the thermoplastic resin (C) as amatrix resin, and the like, the carbon fibers (A) may be provided with asizing agent. Providing the carbon fibers (A) with a sizing agent allowsfor further improving the adhesion of the carbon fibers (A) to thethermoplastic resin (C), as well as the flexural strength and the impactstrength of the molded article.

Specific examples of sizing agents include epoxy resins, phenolicresins, polyethylene glycol, polyurethanes, polyesters, emulsifiers, andsurfactants. These may be used in combination of two or more. The sizingagent is preferably water-soluble or water-dispersible, and epoxy resinswhich have high wettability with the carbon fibers (A) are preferred. Inparticular, polyfunctional epoxy resins are more preferred.

Examples of polyfunctional epoxy resins include bisphenol A epoxyresins, bisphenol F epoxy resins, aliphatic epoxy resins, and phenolnovolac epoxy resins. Among these, aliphatic epoxy resins, which readilyexhibit adhesion to a matrix resin, are preferred. Aliphatic epoxyresins, due to their flexible backbones, tend to have a structure withhigh toughness even at a high crosslink density. The presence of analiphatic epoxy resin between the carbon fibers and the thermoplasticresin makes the fibers flexible and less prone to delamination, therebyallowing for a further improvement in the strength of the resultingmolded article.

Examples of polyfunctional aliphatic epoxy resins include diglycidylether compounds, and polyglycidyl ether compounds. Examples of thediglycidyl ether compounds include ethylene glycol diglycidyl ether,polyethylene glycol diglycidyl ethers, propylene glycol diglycidylether, polypropylene glycol diglycidyl ethers, 1,4-butanediol diglycidylether, neopentyl glycol diglycidyl ether, polytetramethylene glycoldiglycidyl ether, and polyalkylene glycol diglycidyl ethers. Further,examples of the polyglycidyl ether compounds include glycerolpolyglycidyl ether, diglycerol polyglycidyl ether, polyglycerolpolyglycidyl ethers, sorbitol polyglycidyl ether, arabitol polyglycidylether, trimethylolpropane polyglycidyl ethers, trimethylolpropaneglycidyl ether, pentaerythritol polyglycidyl ether, and aliphaticpolyols.

Among the above described aliphatic epoxy resins, trifunctional orhigher aliphatic epoxy resins are preferred, and more preferred arealiphatic polyglycidyl ether compounds containing three or more highlyreactive glycidyl groups. The aliphatic polyglycidyl ether compoundshave a good balance between flexibility, crosslink density, andcompatibility with a matrix resin, and can further improve the adhesion.Among these, glycerol polyglycidyl ether, diglycerol polyglycidyl ether,polyethylene glycol glycidyl ethers, and polypropylene glycol glycidylethers are still more preferred.

The amount of sizing agent deposited is preferably 0.01% by weight ormore and 10% by weight or less based on 100% by weight of the totalweight of the carbon fibers (A) and the sizing agent. When the amount ofsizing agent deposited is 0.01% by weight or more, the adhesion to thethermoplastic resin (C) is further improved. The amount is morepreferably 0.05% by weight or more, and still more preferably 0.1% byweight or more. When the amount of sizing agent deposited is 10% byweight or less, on the other hand, the physical properties of thethermoplastic resin (C) can be maintained at a higher level. The amountis more preferably 5% by weight or less, and more preferably 2% byweight or less. The amount of sizing agent deposited can be determined,for example, by heating the carbon fibers on the surface of which thesizing agent is deposited, at 500° C. for 15 minutes under a nitrogenatmosphere, and calculating the weight of the sizing agent removed byheating at 500° C. for 15 minutes, from the change in weight of thecarbon fibers before and after the heating.

The means of providing a sizing agent is not particularly limited, andexamples thereof include a method in which a sizing agent is dissolvedor dispersed in a solvent (including a dispersion medium, in the case ofdispersing the sizing agent) to prepare a sizing treatment liquid, andthe resulting sizing treatment liquid is applied to the carbon fibers,followed by drying and vaporizing the solvent. Examples of the method ofapplying the sizing treatment liquid to the carbon fibers include:immersing the carbon fibers in the sizing treatment liquid via a roller,bringing the carbon fibers into contact with a roller to which thesizing treatment liquid is attached, and spraying the sizing treatmentliquid onto the carbon fibers in the form of a mist. The method ofapplying the sizing treatment liquid may be a batch method or acontinuous method, but preferred is the continuous method which allowsfor achieving higher productivity and smaller variation. In such a case,it is preferable to control conditions such as the concentration of thesizing treatment liquid, temperature, and yarn tension of the fibers sothat the sizing agent can be deposited on the carbon fibers (A)uniformly and in an amount within an appropriate range. Further, it ismore preferable to excite the carbon fibers (A) with ultrasonic waveswhen providing the sizing treatment liquid.

The drying temperature and the drying time should be adjusted dependingon the amount of sizing agent deposited. To shorten the time required tocompletely remove and dry the solvent used in the sizing treatmentliquid, and at the same time, prevent thermal degradation of the sizingagent and thereby preventing the sized carbon fibers (A) from becomingrigid and poorly spreadable, the drying temperature is preferably 150°C. or more and 350° C. or less, and more preferably 180° C. or more and250° C. or less.

Examples of the solvent to be used in the sizing treatment liquidinclude water, methanol, ethanol, dimethylformamide, dimethylacetamide,and acetone. Among these, water is preferred from the standpoint of easeof handling and disaster prevention. Thus, when a compound insoluble orpoorly soluble in water is used as the sizing agent, it is preferable toadd an emulsifier and a surfactant to prepare an aqueous dispersion.Specific examples of emulsifiers and surfactants that can be usedinclude anionic emulsifiers such as styrene-maleic anhydride copolymers,olefin-maleic anhydride copolymers, naphthalene sulfonate formalincondensates, and sodium polyacrylate; cationic emulsifiers such aspolyethyleneimine and polyvinyl imidazoline; and nonionic emulsifierssuch as nonylphenol ethylene oxide adducts, polyvinyl alcohol,polyoxyethylene ether ester copolymers, and sorbitan ester ethyl oxideadducts. Among these, nonionic emulsifiers which cause littleinteraction are preferred, because they are less likely to inhibit theadhesive effect of functional groups contained in the sizing agent.

In the molded article, the carbon fibers (A) have an average fiberlength (L_(A)) of 0.3 to 3 mm (0.3 mm or more and 3 mm or less). Whenthe average fiber length (L_(A)) of the carbon fibers (A) is less than0.3 mm, the reinforcing effect of the carbon fibers (A) is notsufficiently exhibited in the molded article, resulting in a decrease inthe flexural strength and tensile strength. L_(A) is preferably 0.5 mmor more. When the average fiber length (L_(A)) of the carbon fibers (A)is more than 3 mm, on the other hand, the entanglement between singlefibers of the carbon fibers (A) is increased, making it difficult forthe fibers to be uniformly dispersed in the molded article. As a result,the flexural strength, tensile strength and dispersibility are reduced.L_(A) is preferably 2 mm or less, more preferably 1.5 mm or less, andstill more preferably 1.2 mm or less. The “average fiber length” of thecarbon fibers (A) refers, not to a simple number average value, but toan average fiber length calculated according to the following equationcalculated by applying the method of calculating a weight averagemolecular weight to fiber length calculation, which takes into accountthe contribution of fiber length. Note that the following equation isapplicable when the fiber diameters and density of the carbon fibers (A)are uniform.Average fiber length=Σ(Mi ² ×Ni)/Σ(Mi×Ni)

-   -   Mi: fiber length (mm)    -   Ni: number of carbon fibers having a fiber length Mi

The above described average fiber length can be measured by thefollowing method. A molded article is heated on a hot stage set at 300°C. in a state sandwiched between glass plates, to form a film in whichfibers are uniformly dispersed. The film in which carbon fibers areuniformly dispersed is observed under a light microscope (at 50 to200×). The fiber lengths of randomly selected 1,000 carbon fibers (A)are measured, and the average fiber length (L_(A)) is calculatedaccording to the above equation.

The average fiber length of the carbon fibers (A) in the molded articlecan be adjusted, for example, by varying the conditions of molding, andthe like. Examples of the conditions of molding, in injection molding,include pressure conditions such as back pressure and holding pressure,time conditions such as injection time and pressure holding time, andtemperature conditions such as cylinder temperature and moldtemperature. An increase in the pressure conditions such as backpressure allows for an increase in shearing force within a cylinder,thereby enabling to shorten the average fiber length of the carbonfibers (A). Shortening the injection time also allows for an increase inthe shearing force during the injection, thereby enabling to shorten theaverage fiber length of the carbon fibers (A). Further, a decrease inthe temperature conditions such as cylinder temperature and metal moldtemperature, allows for an increase in the viscosity of the flowingresin and thus an increase in the shearing force, thereby enabling toshorten the average fiber length of the carbon fibers (A). By varyingthe conditions as appropriate and as described above, it is possible toadjust the average fiber length of the carbon fibers (A) in the moldedarticle within a desired range.

The carbon fibers (A) in the molded article preferably have a numberaverage fiber diameter (d_(A)) of 1 to 20 and more preferably 3 to 15from the standpoint of mechanical properties and surface appearance ofthe molded article, but not particularly limited thereto.

The “number average fiber diameter” of the carbon fibers (A) refers toan average fiber diameter calculated according to the followingequation.Number average fiber diameter=Σ/(di×Ni)/Σ(Ni)

-   -   di: fiber diameter (μm)    -   Ni: number of carbon fibers having a fiber diameter di

The number average fiber diameter can be measured by the followingmethod. A molded article is heated on a hot stage set at 300° C. in astate sandwiched between glass plates, to form a film in which fibersare uniformly dispersed. The film in which carbon fibers are uniformlydispersed is observed under a light microscope (at 200 to 1,000×). Thefiber diameters of randomly selected 10 carbon fibers (A) are measured,and the number average fiber diameter is calculated according to theabove equation. The fiber diameter of a carbon fiber as used hereinrefers to, as shown in FIG. 4, a shortest distance (6) between anarbitrary point B on a fiber contour A (4) and a fiber contour A′ (5)opposite to the fiber contour A (4), in each carbon fiber (A) to beobserved. A number average value obtained by: measuring the fiberdiameter at randomly selected 20 locations per one piece of carbon fiber(A); and calculating the average of the measured values at the total 200locations, is defined as the number average fiber diameter. When thenumber of the carbon fibers (A) present within an observation area isless than 10 pieces, the observation area is moved as appropriate to anew area in which 10 pieces of the carbon fibers (A) can be observed.

Since the fiber diameter of a carbon fiber basically does not changebefore and after the molding process, it is possible to adjust the fiberdiameters of the carbon fibers in the molded article, by selecting, asthe carbon fibers to be used in a molding material, carbon fibers havinga desired fiber diameter from among carbon fibers having various fiberdiameters.

The molded article contains the organic fibers (B) in addition to thecarbon fibers (A) described above. Inorganic fibers such as the carbonfibers (A), which are rigid and brittle, are less prone to entanglementbut susceptible to breakage. Thus, a fiber bundle consisting ofinorganic fibers has drawbacks in that it is susceptible to breakageduring the production of a molded article and prone to fall off from themolded article. Incorporation of the organic fibers (B), which areflexible and less susceptible to breakage, can significantly improve theimpact strength of the molded article. The content of the organic fibers(B) in the molded article is 1 to 45 parts by weight (1 part by weightor more and 45 parts by weight or less) based on 100 parts by weight ofthe total amount of the carbon fibers (A), the organic fibers (B) andthe thermoplastic resin (C). When the content of the organic fibers (B)is less than 1 part by weight, the impact properties of the moldedarticle will be reduced. The content of the organic fibers (B) ispreferably 5 parts by weight or more. When the content of the organicfibers (B) is more than 45 parts by weight, on the other hand, theentanglement between fibers will be increased, leading to a decreaseddispersibility of the organic fibers (B) in the molded article, whichoften causes a reduction in the impact strength and a poor surfaceappearance of the molded article. The content of the organic fibers (B)is preferably 30 parts by weight or less.

The organic fibers (B) preferably have a tensile break elongation of 10%or more, and more preferably 20% or more to adjust the average fiberlength of the organic fibers within the range to be described later, andto further improve the impact strength. On the other hand, the organicfibers (B) preferably have a tensile break elongation of 50% or less,and more preferably 40% or less to improve the strength of the fibersand the rigidity of the molded article.

The tensile break elongation (%) of the organic fibers (B) can bemeasured by the following method. A tensile test is carried out in aroom under standard conditions (20° C., 65% RH) at a chuck distance of250 mm and a tensile speed of 300 mm/min, and the length at fiber breakis measured (breakages in the vicinity of chucks are considered as achucking breakage and excluded from the resulting data), calculated tothe second decimal place by the following equation, and rounded to onedecimal place. The average value of the measured values (number of data:n=3) is calculated, and defined as the tensile break elongation.Tensile break elongation (%)=[(length at break (mm)−250)/250]×100

The organic fibers (B) can be selected as appropriate to the extent thatthe mechanical properties of the molded article are not significantlyreduced. Examples thereof include fibers obtained by spinning:polyolefin resins such as polyethylene and polypropylene; polyamideresins such as nylon 6, nylon 66, and aromatic polyamides; polyesterresins such as polyethylene terephthalate and polybutyleneterephthalate; and resins such as polyether ketone, polyether sulfone,polyarylene sulfide, and liquid crystal polyester. These may be used incombination of two or more. The organic fibers (B) are preferablyselected as appropriate from those described above, depending on thecombination with the thermoplastic resin (C), which is a matrix resin.In particular, the organic fibers (B) preferably have a meltingtemperature that is 30° C. to 150° C. higher, and more preferably, 50°C. to 100° C. higher than the molding temperature (melting temperature)of the thermoplastic resin (C). Alternatively, organic fibers (B)obtained using a resin incompatible with the thermoplastic resin (C) arepreferred, because they will be present in the resulting molded articlewhile maintaining their fibrous state, and thus can further improve theimpact strength of the molded article. Examples of the organic fibers(B) having a high melting temperature include polyamide fibers,polyester fibers, polyarylene sulfide fibers, and fluororesin fibers,and it is preferable to use at least one type of fibers selected fromthe group consisting of these fibers, as the organic fibers (B).

In the molded article, the organic fibers (B) have an average fiberlength (L_(B)) of 0.5 mm to 5 mm (0.5 mm or more and 5 mm or less). Whenthe average fiber length (L_(B)) of the organic fibers (B) is less than0.5 mm, the reinforcing effect of the organic fibers (B) is notsufficiently exhibited in the molded article, resulting in a decrease inthe impact strength. L_(B) is preferably 1 mm or more, and morepreferably 1.5 mm or more. When the average fiber length (L_(B)) is morethan 5 mm, on the other hand, the entanglement between single fibers ofthe organic fibers (B) is increased, making it difficult for the fibersto be uniformly dispersed in the molded article. As a result, the impactstrength is reduced. L_(B) is preferably 4 mm or less, and morepreferably 3 mm or less. Similarly to the case of the carbon fibers (A),the “average fiber length” of the organic fibers (B) refers, not to asimple number average value, but to an average fiber length calculatedaccording to the following equation calculated by applying the method ofcalculating a weight average molecular weight to fiber lengthcalculation, which takes into account the contribution of fiber length.Note that the following equation is applicable when the fiber diametersand density of the organic fibers (B) are uniform.Average fiber length=Σ(Mi ² ×Ni)/Σ(Mi×Ni)

-   -   Mi: fiber length (mm)    -   Ni: number of organic fibers having a fiber length Mi

The above described average fiber length can be measured by thefollowing method. A molded article is heated on a hot stage set at 300°C. in a state sandwiched between glass plates, to form a film in whichfibers are uniformly dispersed. The film in which organic fibers areuniformly dispersed is observed under a light microscope (at 50 to200×). The fiber lengths of randomly selected 1,000 organic fibers (B)are measured, and the average fiber length (L_(B)) is calculatedaccording to the above equation.

The average fiber length of the organic fibers (B) in the molded articlecan be adjusted, for example, by appropriately selecting the type of theorganic fibers (B) from those described above, or by varying theconditions of molding and the like. Examples of the conditions ofmolding, in injection molding, include pressure conditions such as backpressure and holding pressure, time conditions such as injection timeand pressure holding time, and temperature conditions such as cylindertemperature and mold temperature. An increase in the pressure conditionssuch as back pressure allows for an increase in the shearing forcewithin a cylinder, thereby enabling to shorten the average fiber lengthof the organic fibers (B). Shortening the injection time also allows foran increase in the shearing force during the injection, thereby enablingto shorten the average fiber length of the organic fibers (B). Further,a decrease in the temperature conditions such as cylinder temperatureand metal mold temperature allows for an increase in the viscosity ofthe flowing resin and thus an increase in the shearing force, therebyenabling to shorten the average fiber length of the organic fibers (B).By varying the conditions as appropriate and as described above, it ispossible to adjust the average fiber length of the organic fibers (B) inthe molded article within a desired range.

The organic fibers (B) in the molded article have a number average fiberdiameter (d_(B)) of 35 to 300 μm (35 μm or more and 300 μm or less).When the organic fibers (B) having a number average fiber diameter(d_(B)) of less than 35 μm are used, larger number of organic fibers areallowed to be present in the resulting molded article, as compared tousing the same weight of the organic fibers having a number averagefiber diameter (d_(B)) of 35 μm or more. Consequently, it is difficultto inhibit entanglement of organic fibers with each other, resulting ina failure to improve the surface appearance of the molded article.Therefore, the organic fibers (B) preferably have a number average fiberdiameter (d_(B)) of 50 μm or more, more preferably 80 μm or more. Whenthe organic fibers (B) have a number average fiber diameter (d_(B)) ofmore than 300 μm, on the other hand, the organic fibers are likely tocause noticeable surface asperity of the molded article, causing a poorsurface appearance, as a result. Thus, the organic fibers (B) preferablyhave a number average fiber diameter (d_(B)) of 150 μm or less.

The “number average fiber diameter” of the organic fibers (B) refers toan average fiber diameter calculated according to the followingequation.Number average fiber diameter=Σ/(di×Ni)/(Ni)

-   -   di: fiber diameter (μm)    -   Ni: number of organic fibers having a fiber diameter di

The number average fiber diameter can be measured by the followingmethod. A molded article is heated on a hot stage set at 300° C. in astate sandwiched between glass plates, to form a film in which fibersare uniformly dispersed. The film in which organic fibers are uniformlydispersed is observed under a light microscope (at 200 to 1,000×). Thefiber diameters of randomly selected 10 organic fibers (B) are measured,and the number average fiber diameter is calculated according to theabove equation. The fiber diameter of an organic fiber as used hereinrefers to, as shown in FIG. 4, the shortest distance (6) between thearbitrary point B on the fiber contour A (4) and the fiber contour A′(5) opposite to the fiber contour A (4), in each organic fiber (B) to beobserved. A number average value obtained by: measuring the fiberdiameter at randomly selected 20 locations per one piece of organicfiber (B); and calculating the average of the measured values at thetotal 200 locations, is defined as the number average fiber diameter.When the number of the organic fibers (B) present within an observationarea is less than 10 pieces, the observation area is moved asappropriate to a new area in which 10 pieces of the organic fibers (B)can be observed.

Since the fiber diameter of an organic fiber basically does not changebefore and after the molding process, it is possible to adjust the fiberdiameters of the organic fibers in the molded article, by selecting, asthe organic fibers to be used in a molding material, organic fibershaving a desired fiber diameter from among organic fibers having variousfiber diameters.

Further, the organic fibers (B) in the molded article preferably have anaspect ratio (L_(B) [μm]/d_(B) [μm]) of 5 to 100 (5 or more and 100 orless). Examples of means of adjusting the aspect ratio in the aboverange include balancing the average fiber length and the number averagefiber diameter. When the aspect ratio of the organic fibers (B) isadjusted to 5 or more, the load applied upon impact can be transmittedto the organic fibers, thereby further improving the impact strength ofthe molded article. Examples of means of adjusting the aspect ratio to 5or more include enlarging the average fiber length L_(B) moderately andreducing the number average fiber diameter d_(B) moderately. The aspectratio is more preferably 10 or more and further preferably 20 or more.On the other hand, when the aspect ratio is adjusted to 100 or less, itis possible to inhibit generating the surface asperity of the moldedarticle due to the organic fibers (B), and a further improved surfaceappearance can be achieved. Examples of means of adjusting the aspectratio to 100 or less include reducing the average fiber length L_(B)moderately and enlarging the number average fiber diameter d_(B)moderately. The aspect ratio is more preferably 70 or less. The aspectratio (L_(B)/d_(B)) as used herein is calculated using the average fiberlength L_(B) and the number average fiber diameter d_(B) describedabove.

The aspect ratio of the organic fibers (B) in the molded article can beadjusted within the above described range, for example, by adjusting theaverage fiber length L_(B) and the number average fiber diameter d_(B)of the organic fibers (B) in the molded article within the abovedescribed preferred ranges.

Further, the ratio (n_(B)/n_(A)) of a calculated number n_(B) of theorganic fibers (B) to a calculated number n_(A) of the carbon fibers (A)in the molded article is preferably 0.001 to 0.01 (0.001 or more and0.01 or less). The calculated number of fibers as used herein is anindicator of the number of the carbon fibers or the organic fibersincluded in 1 g of molded article, and is a numerical value calculatedfrom the number average fiber diameter d (μm), average fiber length L(mm), fiber content w (% by mass), and specific gravity ρ (g/cm³), ofeach type of fibers, according to the following equation.Calculated number of fibers=((1×w/100)/((d/2)² ×πL×ρ))×10⁹

-   -   π: circular constant

When the ratio (n_(B)/n_(A)) of the calculated number of the organicfibers (B) to that of the carbon fibers (A) is 0.001 or more, it meansthat the organic fibers (B) contributing to an improvement in impactresistance are included in a number of 0.1% or more of the number of thecarbon fibers (A). Since the carbon fibers (A) are rigid and brittle,they are less prone to entanglement but susceptible to breakage. Thus,it is possible to further improve the impact strength of the moldedarticle, by allowing the organic fibers (B), which are flexible and lesssusceptible to breakage, to be present in the molded article in a numberof 0.1% or more of the number of the carbon fibers (A). The ratio(n_(B)/n_(A)) of the calculated number is more preferably 0.003 or more.Further, when the ratio (n_(B)/n_(A)) of the calculated number is 0.01or less, the number of the organic fibers (B) can be adjusted to theextent dispersing each organic fiber (B) easily, and the surfaceappearance of the molded article can be improved. The ratio(n_(B)/n_(A)) of the calculated number is more preferably 0.008 or less.

The specific gravity of the carbon fibers (A) or the organic fibers (B)can be measured by retrieving some of the carbon fibers (A) or theorganic fibers (B) from the molded article, and carrying out themeasurement by a liquid immersion method. Specifically, the specificgravity can be determined by performing the measurement of 0.5 g of thecarbon fibers (A) or the organic fibers (B) 3 times, using distilledwater as a liquid to be used in the liquid immersion method, andcalculating the average value of the measured values. To retrieve thecarbon fibers (A) from the molded article, a method can be used in whichthe organic fibers (B) and the matrix resin are removed by heating at aspecific temperature so that the carbon fibers (A) alone remains, or inwhich the molded article is dissolved in a solvent capable of dissolvingthe matrix resin and the organic fibers so that the remaining carbonfibers (A) can be retrieved. To retrieve the organic fibers from themolded article, a method can be used in which the difference in specificgravity between the carbon fibers (A) and the organic fibers (B) areutilized. In this method, the molded article is dissolved in a solventcapable of dissolving the matrix resin alone to retrieve the carbonfibers (A) and the organic fibers (B). The retrieved fibers are thenintroduced, for example, in a solvent having a specific gravity higherthan that of the organic fibers (B) and lower than that of the carbonfibers (A) so that the organic fibers (B) alone will float in thesolvent, thereby enabling to retrieve the organic fibers (B).

The ratio of calculated number of fibers can be adjusted within theabove range, for example, by adjusting the number average fiber diameterand the average fiber length of the organic fibers in the molded articlewithin the above described preferred ranges, or by adjusting the amountsof the carbon fibers (A) and the organic fibers (B) within the abovedescribed preferred ranges.

The molded article contains the thermoplastic resin (C) in an amount of10 to 94 parts by weight (10 parts by weight or more and 94 parts byweight or less) based on 100 parts by weight of the total amount of thecarbon fibers (A), the organic fibers (B) and the thermoplastic resin(C). When the content of the thermoplastic resin (C) is less than 10parts by weight, the dispersibility of the fibers is decreased,resulting in a reduced impact strength. The content of the thermoplasticresin (C) is preferably 20 parts by weight or more, and more preferably30 parts by weight or more. When the content of the thermoplastic resin(C) is more than 94 parts by weight, on the other hand, the relativecontents of the carbon fibers (A) and the organic fibers (B) arereduced, resulting in a decrease in the reinforcing effect provided bythe fibers, and thus, in a decrease in the impact strength. The contentof the thermoplastic resin (C) is preferably 85 parts by weight or less,and more preferably 75 parts by weight or less.

The thermoplastic resin (C) preferably has a molding temperature(melting temperature) of 200 to 450° C. Examples of the thermoplasticresin (C) include polyolefin resins, polystyrene resins, polyamideresins, vinyl halide resins, polyacetal resins, saturated polyesterresins, polycarbonate resins, polyarylsulfone resins, polyarylketoneresins, polyarylene ether resins, polyarylene sulfide resins, polyarylether ketone resins, polyethersulfone resins, polyarylene sulfidesulfone resins, polyarylate resins, liquid crystal polyester resins, andfluororesins. All of these resins act as an electrical insulator. Thesemay be used in combination of two or more. Further, terminal groups inthese resins may be blocked or modified.

Among the thermoplastic resins (C) described above, more preferred arepolyolefin resins, polyamide resins, and polycarbonate resins, which arelightweight and excellent in balance between mechanical properties andmoldability, and still more preferred are polypropylene resins which areexcellent also in chemical resistance and hygroscopicity.

The polypropylene resins may be unmodified or modified.

Specific examples of unmodified polypropylene resins include propylenehomopolymer, and copolymers of propylene and at least one monomerselected from the group consisting of α-olefins, conjugated dienes,non-conjugated dienes and other thermoplastic monomers. Examples of thecopolymers include random copolymers and block copolymers. Examples ofα-olefins include C₂-C₁₂ α-olefins excluding propylene such as ethylene,1-butene, 3-methyl-1-butene, 4-methyl-1-pentene, 3-methyl-1-pentene,4-methyl-1-hexene, 4,4-dimethyl-1-hexene, 1-nonene, 1-octene, 1-heptene,1-hexene, 1-decene, 1-undecene, and 1-dodecene. Examples of conjugateddienes and unconjugated dienes include butadiene, ethylidene norbornene,dicyclopentadiene, and 1,5-hexadiene. These may be used in combinationof two or more. Preferred examples include polypropylene,ethylene-propylene copolymers, propylene-1-butene copolymers, andethylene-propylene-1-butene copolymers. Propylene homopolymer ispreferred from the standpoint of further improving the rigidity of themolded article. A random copolymer or a block copolymer of propylene andan α-olefin, a conjugated diene, a non-conjugated diene and/or the likeis preferred from the standpoint of further improving the impactstrength of the molded article.

The modified polypropylene resin is preferably an acid-modifiedpolypropylene resin, and more preferably an acid-modified polypropyleneresin having a carboxylic acid and/or carboxylate group bound to apolymer chain. The above-described acid-modified polypropylene resin canbe obtained by various methods. For example, the acid-modifiedpolypropylene resin can be obtained by the graft polymerization of anunmodified polypropylene resin with a monomer having a carboxylic acidgroup that is neutralized or not neutralized, and/or a monomer having acarboxylic acid ester group that is saponificated or not saponificated.

Examples of the monomer having a carboxylic acid group that isneutralized or not neutralized and the monomer having a carboxylic acidester group that is saponificated or not saponificated includeethylenically unsaturated carboxylic acids, anhydrides thereof, andesters of ethylenically unsaturated carboxylic acids.

Examples of ethylenically unsaturated carboxylic acids include(meth)acrylic acid, maleic acid, fumaric acid, tetrahydrophthalic acid,itaconic acid, citraconic acid, crotonic acid, and isocrotonic acid.Examples of anhydrides thereof include nadic acid TM(endocis-bicyclo[2,2,1]hept-5-ene-2,3-dicarboxylic acid), maleicanhydride, and citraconic anhydride.

Examples of esters of ethylenically unsaturated carboxylic acids include(meth)acrylic acid esters such as methyl (meth)acrylate, ethyl(meth)acrylate, propyl (meth)acrylate, n-butyl (meth)acrylate, iso-butyl(meth)acrylate, tert-butyl (meth)acrylate, n-amyl (meth)acrylate,isoamyl (meth)acrylate, n-hexyl (meth)acrylate, 2-ethylhexyl(meth)acrylate, octyl (meth)acrylate, decyl (meth)acrylate, dodecyl(meth)acrylate, octadecyl (meth)acrylate, stearyl (meth)acrylate,tridecyl (meth)acrylate, lauroyl (meth)acrylate, cyclohexyl(meth)acrylate, benzyl (meth)acrylate, phenyl (meth)acrylate, isobornyl(meth)acrylate, dicyclopentanyl (meth)acrylate, dicyclopentenyl(meth)acrylate, dimethylaminoethyl (meth)acrylate, and diethylaminoethyl(meth)acrylate; hydroxyl group-containing (meth)acrylic acid esters suchas hydroxyethyl acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl(meth)acrylate, 4-hydroxybutyl acrylate, lactone-modified hydroxyethyl(meth)acrylate, and 2-hydroxy-3-phenoxypropyl acrylate; epoxygroup-containing (meth)acrylic acid esters such as glycidyl(meth)acrylate and methyl glycidyl (meth)acrylate; and aminoalkyl(meth)acrylates such as N,N-dimethylaminoethyl (meth)acrylate,N,N-diethylaminoethyl (meth)acrylate, N,N-dimethylaminopropyl(meth)acrylate, N,N-dipropylaminoethyl (meth)acrylate,N,N-dibutylaminoethyl (meth)acrylate, and N,N-dihydroxyethylaminoethyl(meth)acrylate.

These may be used in combination of two or more. Among these, anhydridesof ethylenically unsaturated carboxylic acids are preferred, and maleicanhydride is more preferred.

To improve the flexural strength and the tensile strength of the moldedarticle, it is preferable to use both an unmodified polypropylene resinand a modified polypropylene resin. Particularly, in terms of thebalance between the flame retardancy and the mechanical properties, itis preferable to use these resins in such amounts that the weight ratioof the unmodified polypropylene resin to the modified polypropyleneresin is 95/5 to 75/25. The weight ratio is more preferably 95/5 to80/20, and still more preferably 90/10 to 80/20.

The polyamide resins are resins produced using amino acids, lactams, ordiamines and dicarboxylic acids as main materials. Typical examples ofthe main materials include amino acids such as 6-aminocaproic acid,11-aminoundecanoic acid, 12-aminododecanoic acid, and p-aminomethylbenzoic acid; lactams such as ε-caprolactam and ω-laurolactam; aliphaticdiamines such as tetramethylenediamine, hexamethylenediamine,2-methylpentamethylenediamine, nonamethylenediamine,undecamethylenediamine, dodecamethylenediamine,2,2,4-/2,4,4-trimethylhexamethylenediamine, and5-methylnonamethylenediamine; aromatic diamines such asm-xylylenediamine and p-xylylenediamine; alicyclic diamines such as1,3-bis(aminomethyl)cyclohexane, 1,4-bis(aminomethyl)cyclohexane,1-amino-3-aminomethyl-3,5,5-trimethylcyclohexane,bis(4-aminocyclohexyl)methane, bis(3-methyl-4-aminocyclohexyl)methane,2,2-bis(4-aminocyclohexyl)propane, bis(aminopropyl)piperazine, andaminoethylpiperazine; aliphatic dicarboxylic acids such as adipic acid,suberic acid, azelaic acid, sebacic acid, and dodecanedioic acid;aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid,2-chloroterephthalic acid, 2-methylterephthalic acid,5-methylisophthalic acid, 5-sodium sulfoisophthalic acid,hexahydroterephthalic acid, and hexahydroisophthalic acid; and alicyclicdicarboxylic acids such as 1,4-cyclohexanedicarboxylic acid,1,3-cyclohexanedicarboxylic acid, and 1,2-cyclohexanedicarboxylic acid.These may be used in combination of two or more.

Polyamide resins having a melting point of 200° C. or higher, which areexcellent in heat resistance and strength, are particularly useful.Specific examples thereof include polycaproamide (nylon 6),polyhexamethylene adipamide (nylon 66), polycaproamide/polyhexamethyleneadipamide copolymer (nylon 6/66), polytetramethylene adipamide (nylon46), polyhexamethylene sebacamide (nylon 610), polyhexamethylenedodecamide (nylon 612), polyhexamethylene terephthalamide/polycaproamidecopolymer (nylon 6T/6), polyhexamethylene adipamide/polyhexamethyleneterephthalamide copolymer (nylon 66/6T), polyhexamethyleneadipamide/polyhexamethylene isophthalamide copolymer (nylon 66/6I),polyhexamethylene adipamide/polyhexamethyleneterephthalamide/polyhexamethylene isophthalamide copolymer (nylon66/6T/6I), polyhexamethylene terephthalamide/polyhexamethyleneisophthalamide copolymer (nylon 6T/6I), polyhexamethyleneterephthalamide/polydodecane amide copolymer (nylon 6T/12),polyhexamethylene terephthalamide/poly(2-methylpentamethylene)terephthalamide copolymer (nylon 6T/M5T), polyxylylene adipamide (nylonXD6), polynonamethylene terephthalamide (nylon 9T), and copolymersthereof. These may be used in combination of two or more. Among these,nylon 6 and nylon 66 are more preferred.

The degree of polymerization of the polyamide resins is not particularlylimited. However, preferred are polyamide resins having a relativeviscosity, as measured at 25° C. in a solution of 0.25 g of polyamideresin in 25 mL of 98% concentrated sulfuric acid of 1.5 to 5.0, and morepreferably 2.0 to 3.5.

The polycarbonate resins are obtained by allowing a dihydric phenol toreact with a carbonate precursor. Copolymers obtained using two or moredihydric phenols or two or more carbonate precursors may be used.Examples of the reaction method include interfacial polymerization, melttransesterification, solid phase transesterification of a carbonateprepolymer, and ring-opening polymerization of a cyclic carbonatecompound. For example, the polycarbonate resin disclosed in JP2002-129027 A can be used.

Examples of dihydric phenols include1,1-bis(4-hydroxyphenyl)-3,3,5-trimethylcyclohexane,bis(4-hydroxyphenyl)alkane (e.g., bisphenol A),2,2-bis{(4-hydroxy-3-methyl)phenyl}propane,α,α′-bis(4-hydroxyphenyl)-m-diisopropylbenzene, and9,9-bis(4-hydroxy-3-methylphenyl)fluorene. These may be used incombination of two or more. Among these, preferred is bisphenol A whichcan provide a polycarbonate resin with higher impact resistance. On theother hand, copolymers obtained using bisphenol A and any other dihydricphenol are excellent in high heat resistance or low water absorption.

Examples of carbonate precursors include carbonyl halides, carbonic aciddiesters, and haloformates, and specific examples include phosgene,diphenyl carbonate, and dihaloformates of a dihydric phenol.

In the production of a polycarbonate resin from such a dihydric phenoland a carbonate precursor, any of catalysts, terminal blocking agents,antioxidants for preventing oxidation of the dihydric phenol, and thelike may be used, as necessary.

Further, the polycarbonate resin may be: a branched polycarbonate resinobtained by copolymerization of a polyfunctional aromatic compound oftrifunctional or higher; a polyester carbonate resin obtained bycopolymerization of an aromatic or aliphatic (including alicyclic)difunctional carboxylic acid; a copolymerized polycarbonate resinobtained by copolymerization of a difunctional aliphatic (includingalicyclic) alcohol; or a polyester carbonate resin obtained bycopolymerization of both of such a difunctional carboxylic acid and adifunctional aliphatic alcohol. These polycarbonate resins may be usedin combination of two or more.

The molecular weight of the polycarbonate resin is not particularlylimited, but preferably 10,000 to 50,000 in terms of viscosity averagemolecular weight. A viscosity average molecular weight of 10,000 or morecan further improve the strength of the molded article. The viscosityaverage molecular weight is more preferably 15,000 or more, and stillmore preferably 18,000 or more. A viscosity average molecular weight of50,000 or less, on the other hand, improves moldability. The viscosityaverage molecular weight is more preferably 40,000 or less, and stillmore preferably 30,000 or less. When two or more polycarbonate resinsare used, it is preferred that at least one of the polycarbonate resinshave a viscosity average molecular weight within the range describedabove. In such a case, the other polycarbonate resin(s) preferablyhas/have a viscosity average molecular weight of more than 50,000, andpreferably more than 80,000. Such a polycarbonate resin has a highentropy elasticity, and thus is advantageous when molding such asgas-assisted molding is used in combination, and at the same time,exhibits properties derived from the high entropy elasticity (anti-dripproperties, drawdown properties, and properties of improving meltproperties such as jetting).

The viscosity average molecular weight (M) of the polycarbonate resin isa value determined by measuring a specific viscosity (η_(sp)) of asolution of 0.7 g of the polycarbonate resin in 100 mL of methylenechloride, at 20° C., and substituting the specific viscosity (η_(sp))into the following equation.η_(sp) /c=[η]+0.45×[η]² (where [η] is a limiting viscosity)

-   -   [η]=1.23×10⁻⁴×M^(0.83)    -   c=0.7

The molded article preferably includes a compound (D) having a meltviscosity at 200° C. that is lower than that of the thermoplastic resin(C), in addition to the carbon fibers (A), the organic fibers (B), andthe thermoplastic resin (C). The melt viscosity at 200° C. of thecompound (D) having a melt viscosity at 200° C. that is lower than thatof the thermoplastic resin (C) (sometimes referred to as “compound (D)”)is preferably 5 Pa·s or lower, more preferably 2 Pa·s or lower, andstill more preferably 1.5 Pa·s or lower. Adjusting the melt viscosity at200° C. within this range allows for a further improvement in thedispersibility of the carbon fibers (A) and the organic fibers (B)during the molding, as well as a further improvement in the flexuralstrength and the tensile strength of the resulting molded article. Themelt viscosity at 200° C. of the thermoplastic resin (C) and thecompound (D) can be measured with a viscoelasticity meter at 0.5 Hzusing a 40-mm parallel plate.

The molded article can be obtained by using the molding material to bedescribed later. In the production of the molding material, a roving ofcarbon fibers (A), a roving of organic fibers (B), or a fiber bundle (E)including the carbon fibers (A) and organic fibers (B) is preparedfirst, as will be described later. Subsequently, the roving of thecarbon fibers (A), the roving of the organic fibers (B), or the fiberbundle (E) is impregnated with a molten compound (D), to produce acomposite (G), (J), or (F), respectively. At this time, since thecompound (D) is preferably supplied at a melting temperature(temperature in the melting bath) of 100 to 300° C., we paid attentionto the melt viscosity at 200° C. of the compound (D) as an indicator ofthe impregnation of the compound (D) into the roving of the carbonfibers (A), the roving of the organic fibers (B), or the fiber bundle(E). When the melt viscosity at 200° C. is within the above describedpreferred range, the compound (D) exhibits excellent impregnation,within the above described preferred range of the melting temperature.As a result, the dispersibility of the carbon fibers (A) and the organicfibers (B) is further improved, thereby enabling to further improve theimpact strength of the molded article.

The compound (D) may be, for example, a compound having a number averagemolecular weight of 200 to 50,000. The compound having a number averagemolecular weight of 200 to 50,000 is typically a solid that isrelatively brittle and easily broken, or a liquid, at normaltemperature. Such a compound, due to its low molecular weight, is highlyflowable, and can enhance the dispersion of the carbon fibers (A) andthe organic fibers (B) in the thermoplastic resin (C). In other words,when the compound (D) has a number average molecular weight of 200 ormore, it is possible to further improve the mechanical properties,particularly, the flexural strength and tensile strength, of the moldedarticle. The number average molecular weight is more preferably 1,000 ormore. When the compound (D) has a number average molecular weight of50,000 or less, on the other hand, the compound has an adequately lowviscosity, and thus exhibits excellent impregnation into the carbonfibers (A) and the organic fibers (B) contained in the molded article.As a result, the dispersibility of the carbon fibers (A) and the organicfibers (B) in the molded article can further be improved. The numberaverage molecular weight is more preferably 3,000 or less. The numberaverage molecular weight of such a compound can be determined using gelpermeation chromatography (GPC).

The compound (D) preferably has a high affinity to the thermoplasticresin (C). Selecting a compound (D) having a high affinity to thethermoplastic resin (C) facilitates the compatibility of the compound(D) with the thermoplastic resin (C), as a result of which thedispersibility of the carbon fibers (A) and the organic fibers (B) canfurther be improved.

The compound (D) is selected as appropriate depending on the combinationwith the thermoplastic resin (C), which is a matrix resin. For example,when the molding temperature is 150° C. to 270° C., a terpene resin issuitably used, and when the molding temperature is 270° C. to 320° C.,an epoxy resin is suitably used. Specifically, when the thermoplasticresin (C) is a polypropylene resin, the compound (D) is preferably aterpene resin. When the thermoplastic resin (C) is a polycarbonateresin, the compound (D) is preferably an epoxy resin. When thethermoplastic resin (C) is a polyamide resin, the compound (D) ispreferably a terpene phenol resin.

The content of the compound (D) in the molded article is preferably 1 to25 parts by weight (1 part by weight or more and 25 parts by weight orless) based on 100 parts by weight of the total amount of the carbonfibers (A), the organic fibers (B), and the thermoplastic resin (C).When the content of the compound (D) is 1 part by weight or more, theflowability of the carbon fibers (A) and the organic fibers (B) in themolded article is further improved, resulting in a further improvementin the dispersibility. The content is more preferably 2 parts by weightor more, and still more preferably 4 parts by weight or more. When thecontent of the compound (D) is 25 parts by weight or less, on the otherhand, the flexural strength, tensile strength, and impact strength ofthe molded article can further be improved. The content is morepreferably 20 parts by weight or less, and still more preferably 15parts by weight or less.

The compound (D) preferably shows a weight loss on heating at themolding temperature, as measured at a heating rate of 10° C./min (inair), of 5% by weight or less. When the weight loss on heating is 5% byweight or less, generation of decomposition gas can be reduced duringimpregnation of the carbon fibers (A) and the organic fibers (B) withthe compound (D), allowing for a reduction in void formation during themolding process. The gas generation can be reduced particularly inhigh-temperature molding. The weight loss on heating is more preferably3% by weight or less.

The weight loss on heating at the molding temperature of the compound(D) as used herein refers to a weight reduction ratio of the weight ofthe compound (D) after heating under the above described heatingcondition, with respect to the weight of the compound (D) before theheating, which is taken as 100%. The above descried weight loss onheating can be determined according to the following equation. Theweights of the compound (D) before and after heating can be determinedby measuring the weights thereof before and after the heating at themolding temperature by thermogravimetric analysis (TGA) using a platinumsample pan in an air atmosphere at a heating rate of 10° C./min.Weight loss on heating [% by weight]={(weight before heating−weightafter heating)/weight before heating}×100

The epoxy resin suitably used as the compound (D) refers to a compoundhaving two or more epoxy groups, wherein the compound includessubstantially no curing agent, and does not undergo curing due toso-called three-dimensional cross-linking even under heating. Thecompound (D) preferably has a glycidyl group, which facilitatesinteraction with the carbon fibers (A) and the organic fibers (B),compatibility with a fiber bundle (E), and impregnation. Further,dispersibility of the carbon fibers (A) and the organic fibers (B)during molding further improves.

Examples of the compound having a glycidyl group include glycidyl etherepoxy resins, glycidyl ester epoxy resins, glycidyl amine epoxy resins,and alicyclic epoxy resins. These may be used in combination of two ormore.

Examples of glycidyl ether epoxy resins include bisphenol A epoxyresins, bisphenol F epoxy resins, bisphenol AD epoxy resins, halogenatedbisphenol A epoxy resins, bisphenol S epoxy resins, resorcinol epoxyresins, hydrogenated bisphenol A epoxy resins, phenol novolac epoxyresins, cresol novolac epoxy resins, aliphatic epoxy resins having anether bond, naphthalene epoxy resins, biphenyl epoxy resins, biphenylaralkyl epoxy resins, and dicyclopentadiene epoxy resins.

Examples of glycidyl ester epoxy resins include hexahydrophthalic acidglycidyl ester and dimer acid diglycidyl ester.

Examples of glycidyl amine epoxy resins include triglycidylisocyanurate, tetraglycidyl diaminodiphenylmethane, tetraglycidylm-xylenediamine, and aminophenol epoxy resins.

Examples of alicyclic epoxy resins include 3,4-epoxy-6-methylcyclohexylmethyl carboxylate and 3,4-epoxycyclohexylmethyl carboxylate.

Above all, in terms of excellent balance between viscosity and heatresistance, glycidyl ether epoxy resins are preferred, and bisphenol Aepoxy resins and bisphenol F epoxy resins are more preferred.

The number average molecular weight of the epoxy resin used as thecompound (D) is preferably 200 to 5,000. When the number averagemolecular weight of the epoxy resin is 200 or more, the mechanicalproperties of the molded article can further be improved. The numberaverage molecular weight of the epoxy resin is more preferably 800 ormore, and still more preferably 1,000 or more. When the number averagemolecular weight of the epoxy resin is 5,000 or less, on the other hand,excellent impregnation into the fiber bundle (E) is exhibited, and thedispersibility of the carbon fibers (A) and the organic fibers (B) canfurther be improved. The number average molecular weight of the epoxyresin is more preferably 4,000 or less, and still more preferably 3,000or less. The number average molecular weight of the epoxy resin can bedetermined using gel permeation chromatography (GPC).

Examples of terpene resins include polymers and copolymers obtained bypolymerization of terpene monomers, optionally with aromatic monomers,in an organic solvent in the presence of a Friedel-Crafts catalyst.

Examples of terpene monomers include monocyclic monoterpenes such asα-pinene, β-pinene, dipentene, d-limonene, myrcene, allo-ocimene,ocimene, α-phellandrene, α-terpinene, γ-terpinene, terpinolene,1,8-cineol, 1,4-cineol, α-terpineol, α-terpineol, γ-terpineol, sabinene,p-menthadienes, and carenes. Examples of aromatic monomers includestyrene and α-methyl styrene.

Among these, α-pinene, β-pinene, dipentene, and d-limonene, which havehigh compatibility with the thermoplastic resin (C), are preferred, andhomopolymers of these terpene monomers are more preferred. Further,hydrogenated terpene resins obtained by hydrogenation of these terpeneresins are preferred, since they have an even higher compatibility withthe thermoplastic resin (C), particularly, with a polypropylene resin.

The glass transition temperature of the terpene resin is preferably 30to 100° C., but not particularly limited thereto. A glass transitiontemperature of 30° C. or higher facilitates the handling of the compound(D) during molding. A glass transition temperature of 100° C. or lowermakes it possible to moderately control the compound (D) during molding,leading to improved moldability.

The number average molecular weight of the terpene resin is preferably200 to 5,000. When the number average molecular weight is 200 or more,the mechanical properties, particularly, the flexural strength andtensile strength of the molded article can further be improved. When thenumber average molecular weight is 5,000 or less, on the other hand, theterpene resin has an adequately low viscosity, and thus exhibitsexcellent impregnation. As a result, dispersibility of the carbon fibers(A) and the organic fibers (B) in the molded article can further beimproved. The number average molecular weight of the terpene resin canbe determined using gel permeation chromatography (GPC).

The terpene phenol resin is obtained by allowing a terpene monomer toreact with a phenol, using a catalyst. A preferred phenol is one havingon its benzene ring 1 to 3 groups selected from the group consisting ofalkyl groups, halogen atoms and hydroxyl groups. Specific examplesthereof include cresol, xylenol, ethylphenol, butylphenol,t-butylphenol, nonylphenol, 3,4,5-trimethylphenol, chlorophenol,bromophenol, chlorocresol, hydroquinone, resorcinol, and orcinol. Thesemay be used in combination of two or more. Among these, phenol andcresol are preferred.

The number average molecular weight of the terpene phenol resin ispreferably 200 to 5,000. When the number average molecular weight is 200or more, the flexural strength and tensile strength of the moldedarticle can further be improved. When the number average molecularweight is 5,000 or less, on the other hand, the terpene phenol resin hasan adequately low viscosity, and thus exhibits excellent impregnation.As a result, dispersibility of the carbon fibers (A) and the organicfibers (B) in the molded article can further be improved. The numberaverage molecular weight of the terpene phenol resin can be determinedusing gel permeation chromatography (GPC).

The molded article may contain other components in addition to the abovedescribed components (A) to (D), to the extent that the desired effectis not impaired. Examples of other components include thermosettingresins, inorganic fillers other than carbon fibers, flame retardants,conductivity-imparting agents, crystal nucleating agents, UV absorbers,antioxidants, vibration dampers, antimicrobial agents, insectrepellents, deodorizers, stain inhibitors, heat stabilizers, moldreleasing agents, antistatic agents, plasticizers, lubricants, coloringagents, pigments, dyes, foaming agents, foam suppressors, and couplingagents.

A method of producing the molded article will now be described.

The molded article can be obtained preferably by molding the moldingmaterial to be described later. Examples of molding methods includeinjection molding, autoclave molding, press molding, filament windingmolding, and stamping molding, which are excellent in productivity.These may be used in combination of two or more. An integrated moldingmethod such as insert molding or outsert molding can also be used.Further, it is also possible to perform, after the molding process, acorrection treatment by heating, or a bonding technique excellent inproductivity such as heat welding, vibration welding, or ultrasonicwelding. Among these, preferred is a molding method using a mold. Inparticular, a molding method using an injection molding machine allowsfor producing molded articles continuously and stably. The conditions ofinjection molding are not particularly limited, and preferred conditionsare, for example, as follows: injection time: 0.5 seconds to 10 seconds,more preferably 2 seconds to 10 seconds; back pressure: 0.1 MPa to 10MPa, more preferably 2 MPa to 8 MPa; holding pressure: 1 MPa to 50 MPa,more preferably 1 MPa to 30 MPa; pressure holding time: 1 second to 20seconds, more preferably 5 seconds to 20 seconds; cylinder temperature:200° C. to 320° C.; and mold temperature: 20° C. to 100° C. The cylindertemperature as used herein refers to the temperature of a portion usedto heat and melt a molding material in the injection molding machine,and the mold temperature refers to the temperature of a mold into whicha resin is injected to be formed into a desired shape. By appropriatelyselecting these conditions, particularly, the injection time, backpressure, and mold temperature, the length of reinforcement fibers inthe resulting molded article can be easily adjusted.

The fiber reinforced thermoplastic resin molding material (sometimesreferred to as “molding material”) that is suitable to produce themolded article will now be described. (1) A fiber reinforcedthermoplastic resin molding material (hereinafter sometimes referred toas “molding material according to a first example”), or (2) a moldingmaterial (hereinafter sometimes referred to as “molding materialaccording to a second example”) can be suitably used as a moldingmaterial to produce the molded article. The molding material accordingto the first example comprises 5 to 45 parts by weight (5 parts byweight or more and 45 parts by weight or less) of carbon fibers (A), 1to 45 parts by weight (1 part by weight or more and 45 parts by weightor less) of organic fibers (B), 10 to 94 parts by weight (10 parts byweight or more and 94 parts by weight or less) of a thermoplastic resin(C), and 1 to 25 parts by weight (1 part by weight or more and 25 partsby weight or less) of a compound (D) having a melt viscosity at 200° C.that is lower than that of the thermoplastic resin (C), based on 100parts by weight of the total amount of the carbon fibers (A), theorganic fibers (B), and the thermoplastic resin (C), wherein: theorganic fibers (B) have a number average fiber diameter (d_(B)) of 35 to300 μm (35 μm or more and 300 μm or less); the thermoplastic resin (C)is contained at the outer side of a composite (F) obtained byimpregnating a fiber bundle (E) comprising the carbon fibers (A) and theorganic fibers (B) with the compound (D); the carbon fibers (A) and theorganic fibers (B) are unevenly distributed in a cross section of thefiber bundle (E); and the length of the fiber bundle (E) and the lengthof the fiber reinforced thermoplastic resin molding material aresubstantially the same. The molding material according to the secondexample comprises: a carbon fiber reinforced thermoplastic resin moldingmaterial (X) comprising 5 to 45 parts by weight (5 parts by weight ormore and 45 parts by weight or less) of carbon fibers (A), 35 to 94parts by weight (35 parts by weight or more and 94 parts by weight orless) of a thermoplastic resin (C), and 1 to 25 parts by weight (1 partby weight or more and 25 parts by weight or less) of a compound (D)having a melt viscosity at 200° C. that is lower than that of thethermoplastic resin (C), based on 100 parts by weight of the totalamount of the carbon fibers (A), the thermoplastic resin (C), and thecompound (D) having a melt viscosity at 200° C. that is lower than thatof the thermoplastic resin (C), wherein the thermoplastic resin (C) iscontained at the outer side of a composite (G) obtained by impregnatingthe carbon fibers (A) with the compound (D), and the length of thecarbon fibers (A) and the length of the carbon fiber reinforcedthermoplastic resin molding material are substantially the same; and anorganic fiber reinforced thermoplastic resin molding material (Y)comprising 1 to 45 parts by weight (1 part by weight or more and 45parts by weight or less) of organic fibers (B), 35 to 94 parts by weight(35 parts by weight or more and 94 parts by weight or less) of athermoplastic resin (H), and 1 to 25 parts by weight (1 part by weightor more and 25 parts by weight or less) of a compound (I) having a meltviscosity at 200° C. that is lower than that of the thermoplastic resin(H), based on 100 parts by weight of the total amount of the organicfibers (B), the thermoplastic resin (H), and the compound (I), whereinthe organic fibers (B) have a number average fiber diameter (d_(B)) of35 to 300 μm (35 μm or more and 300 μm or less).

First, the molding material according to the first example will bedescribed. The molding material according to the first example used toproduce the molded article described above comprises at least carbonfibers (A), organic fibers (B), a thermoplastic resin (C), and acompound (D), and the organic fibers (B) have a number average fiberdiameter (d_(B)) of 35 to 300 μm (35 μm or more and 300 μm or less).Further, the molding material according to the first example has astructure comprising a composite (F) obtained by impregnating a fiberbundle (E) comprising the carbon fibers (A) and the organic fibers (B)with the compound (D), the thermoplastic resin (C) being contained atthe outer side of the composite (F). The effects provided by the carbonfibers (A), the organic fibers (B), the thermoplastic resin (C), and thecompound (D) are as described above in the description of the moldedarticle.

The molding material according to the first example has the composite(F) in which the carbon fibers (A) and the organic fibers (B) in theform of a continuous fiber bundle are present inside the thermoplasticresin (C), and the gaps between the single fibers of the carbon fibers(A) and the organic fibers (B) are filled with the compound (D). Thecomposite (F) has a structure in which the carbon fibers (A) and theorganic fibers (B) are dispersed like islands in a sea of the compound(D).

The molding material according to the first example comprises thethermoplastic resin (C) at the outer side of the composite (F) obtainedby impregnating the fiber bundle (E) with the compound (D). A preferredstructure is one in which the thermoplastic resin (C) is disposed tosurround the composite (F) in a cross section perpendicular to thelonger direction of the molding material, or one in which the composite(F) and the thermoplastic resin (C) are disposed in layers, thethermoplastic resin (C) being the outermost layer in a cross sectionperpendicular to the longer direction of the molding material.

In the molding material according to the first example, the compound(D), in most cases, is a low molecular weight compound, and is typicallyin the form of a solid that is relatively brittle and easily broken, ora liquid, at normal temperature. The structure in which thethermoplastic resin (C) is contained at the outer side of the composite(F) allows the thermoplastic resin (C) having a high molecular weight toprotect the composite (F), to prevent the destruction, scattering andthe like of the compound (D) due to impact, abrasion and the like duringconveyance and handling of the molding material, and to retain the shapeof the molding material. From the standpoint of handleability, themolding material preferably keeps the above-described shape until beingsubjected to molding.

The composite (F) and the thermoplastic resin (C) may be such that thecomposite (F) and the thermoplastic resin (C) which has partiallypenetrated into a portion of the composite (F) at or near theirinterface are mixing with each other, or that the fiber bundle (E) isimpregnated with the thermoplastic resin (C).

In the molding material according to the first example, the carbonfibers (A) and the organic fibers (B) are preferably unevenlydistributed in a cross section of the fiber bundle (E). The crosssection of the fiber bundle (E) as used herein refers to a cross sectionof the fiber bundle (E) perpendicular to the longer direction of fiber.When the carbon fibers (A) and the organic fibers (B) are unevenlydistributed in a cross section of the fiber bundle (E), the entanglementbetween the carbon fibers (A) and the organic fibers (B) during moldingcan be prevented, thereby enabling to produce a molded article in whichthe carbon fibers (A) and the organic fibers (B) are uniformlydispersed. As a result, the impact strength of the molded article canfurther be improved. The expression “unevenly distributed” means that,in a cross section of the fiber bundle (E), the carbon fibers (A) andthe organic fibers (B) are not uniformly present throughout the entireregion, but present unevenly at some parts. Examples in which the fibersare “unevenly distributed” include: so-called core-in-sheath structuressuch as an example where the carbon fibers (A) envelop the organicfibers (B) in a cross section of the fiber bundle (E), as shown in FIG.1, and an example where the organic fibers (B) envelop the carbon fibers(A), as shown in FIG. 2; and a structure in which a bundle of the carbonfibers (A) and a bundle of the organic fibers (B) are present separatedby a certain boundary in a cross section of the fiber bundle (E), asshown in FIG. 3. The term “envelop” refers to a state in which thecarbon fibers (A) are disposed at the core and the organic fibers (B) atthe sheath, or a state in which the organic fibers (B) are disposed atthe core and the carbon fibers (A) at the sheath. In the example shownin FIG. 3, at least a portion of the carbon fibers (A) and at least aportion of the organic fibers (B) are both in contact with thethermoplastic resin (C) at the outer side, in a cross section of thefiber bundle (E). In this case, examples where the carbon fibers (A) orthe organic fibers (B) are in contact with the thermoplastic resin (C)are intended to encompass examples where the carbon fibers (A) or theorganic fibers (B) are in contact with the thermoplastic resin (C) viathe compound (D).

To confirm that the carbon fibers (A) and the organic fibers (B) areunevenly distributed in a cross section of the fiber bundle (E), forexample, a method can be used in which a cross section perpendicular tothe longer direction of fiber of the molding material is observed undera light microscope at a magnification of 300×, and the micrographobtained is subjected to image processing to be analyzed.

To allow the carbon fibers (A) and the organic fibers (B) to be unevenlydistributed in a cross section of the fiber bundle (E), a method can beused, for example, in which the molding material is produced in a statewhere a bundle of the carbon fibers (A) and a bundle of the organicfibers (B) are aligned. When the molding material is produced in a statewhere the respective bundles are aligned, the carbon fibers (A) and theorganic fibers (B) are allowed to exist as separate fiber bundles,thereby enabling the carbon fibers (A) and the organic fibers (B) to beunevenly distributed. Increasing in the number of single fibers in thebundle of the carbon fibers (A) and the bundle of the organic fibers (B)to be used allows for an increase in the size of the bundles, andreducing the number of the single fibers in the bundles allows for adecrease in the size of the bundles. In this manner, it is possible toallow the fibers (A) and (B) to be unevenly distributed while varyingthe size of the bundles.

In the molding material according to the first example, the length ofthe fiber bundle (E) is preferably substantially the same as the lengthof the molding material. When the length of the fiber bundle (E) issubstantially the same as the length of the molding material, theresulting molded article can contain the carbon fibers (A) and theorganic fibers (B) having a long fiber length, and thus can have moreexcellent mechanical properties. The length of the molding materialrefers to a length thereof in the orientation direction of the fiberbundle (E) in the molding material. Further, the expression“substantially the same length” means that the fiber bundle (E) is notcut intentionally in the molding material, or that the fiber bundle (E)significantly shorter than the overall length of the molding material issubstantially absent. Although the amount of the fiber bundle (E)shorter than the overall length of the molding material is not limitedto a particular value, the content of the fiber bundle (E) having alength that is 50% or less of the overall length of the molding materialis preferably 30% by mass or less, and more preferably 20% by mass orless, with respect to the total amount of the fiber bundle (E). Themolding material is preferably continuous and has a cross-sectionalshape that is substantially the same across the longer direction.

The length of the molding material according to the first example istypically 3 mm to 15 mm.

As the components (A) to (D) of the molding material according to thefirst example, it is possible to use the components (A) to (D) describedabove in the section of the molded article. In addition, the othercomponents exemplified for the molded article can be contained.

The molding material according to the first example contains the carbonfibers (A) in an amount of 5 to 45 parts by weight (5 parts by weight ormore and 45 parts by weight or less) based on 100 parts by weight of thetotal amount of the carbon fibers (A), the organic fibers (B), and thethermoplastic resin (C). To further improve the flexural properties andthe impact strength of the molded article, the content of the carbonfibers (A) is more preferably 10 parts by weight or more. To improve thedispersibility of the carbon fibers (A) in the molded article andfurther improve the impact strength of the molded article, the contentof the carbon fibers (A) is more preferably 30 parts by weight or less.Further, the molding material according to the first example containsthe organic fibers (B) in an amount of 1 to 45 parts by weight (1 partby weight or more and 45 parts by weight or less) based on 100 parts byweight of the total amount of the above described components (A) to (C).To further improve the impact properties of the molded article, thecontent of the organic fibers (B) is preferably 5 parts by weight ormore. To improve the dispersibility of the organic fibers (B) in themolded article and further improve the impact strength of the moldedarticle, the content of the organic fibers (B) is more preferably 30parts by weight or less. Further, the molding material according to thefirst example contains the thermoplastic resin (C) in an amount of 10 to94 parts by weight (10 parts by weight or more and 94 parts by weight orless) based on 100 parts by weight of the total amount of the components(A) to (C). The content of the thermoplastic resin (C) is preferably 20parts by weight or more, and more preferably 30 parts by weight or more.To further improve the impact strength of the molded article, thecontent of the thermoplastic resin (C) is preferably 85 parts by weightor less, and more preferably 75 parts by weight or less. Further, themolding material according to the first example contains the compound(D) in an amount of 1 to 25 parts by weight (1 part by weight or moreand 25 parts by weight or less) based on 100 parts by weight of thetotal amount of the components (A) to (C). To improve the flowabilityand dispersibility of the carbon fibers (A) and the organic fibers (B)during molding, the content of the compound (D) is more preferably 2parts by weight or more, and still more preferably 4 parts by weight ormore. On the other hand, to further improve the flexural strength,tensile strength and impact strength of the molded article, the contentof the compound (D) is more preferably 20 parts by weight or less, andstill more preferably 15 parts by weight or less.

The organic fibers (B) in the molding material according to the firstexample have a number average fiber diameter (d_(B)) of 35 to 300 μm (35μm or more and 300 μm or less). Since the number average fiber diameter(d_(B)) of the organic fibers (B) generally does not change before andafter the production process of the molding material, it is possible toeasily adjust the number average fiber diameter (d_(B)) of the organicfibers (B) in the molding material within the above described desiredrange, by adjusting the number average fiber diameter (d_(B)) of theorganic fibers (B) as a raw material to 35 to 300 The number averagefiber diameter (d_(B)) of the organic fibers (B) in the molding materialis more preferably 50 μm or more and 150 μm or less.

The “number average fiber diameter” of the organic fibers (B) refers toan average fiber diameter calculated according to the followingequation.Number average fiber diameter=Σ/(di×Ni)/Σ(Ni)

-   -   di: fiber diameter (μm)    -   Ni: number of organic fibers having a fiber diameter di

The number average fiber diameter of the organic fibers in the moldingmaterial can be determined in the same manner as the number averagefiber diameter of the organic fibers in the molded article.

Next, the molding material according to the second example will bedescribed. The molding material according to the second example used toproduce the molded article described above comprises a carbon fiberreinforced thermoplastic resin molding material (X) (sometimes referredto as “carbon fiber reinforced molding material”) comprising at leastcarbon fibers (A), a thermoplastic resin (C), and a compound (D) havinga melt viscosity at 200° C. that is lower than that of the thermoplasticresin (C); and an organic fiber reinforced thermoplastic resin moldingmaterial (Y) (sometimes referred to as “organic fiber reinforced moldingmaterial”) comprising at least organic fibers (B), a thermoplastic resin(H) and a compound (I) having a melt viscosity at 200° C. that is lowerthan that of the thermoplastic resin (H) (sometimes referred to as“compound (I)”), wherein the organic fibers (B) have a number averagefiber diameter (d_(B)) of 35 to 300 μm (35 μm or more and 300 μm orless). The carbon fiber reinforced molding material (X) preferably has astructure comprising a composite (G) obtained by impregnating the carbonfibers (A) with the compound (D), the thermoplastic resin (C) beingcontained at the outer side of the composite (G). The organic fiberreinforced molding material (Y) has a structure comprising a composite(J) obtained by impregnating the organic fibers (B) with the compound(I), the thermoplastic resin (H) being contained at the outer side ofthe composite (J). The effects provided by the carbon fibers (A) and theorganic fibers (B) are as described above in the description of themolded article. The thermoplastic resin (C) and the thermoplastic resin(H), which are matrix resins having a relatively high viscosity andexcellent physical properties such as toughness, are impregnated intothe carbon fibers (A) or the organic fibers (B) during molding to firmlyhold the carbon fibers (A) or the organic fibers (B) in the moldedarticle. As the thermoplastic resin (H), any of the resins exemplifiedfor the above described thermoplastic resin (C) can be used, and thethermoplastic resin (C) and the thermoplastic resin (H) may be the sameas, or different from, each other. The compound (D) and the compound (I)each form a composite together with the carbon fibers (A) or the organicfibers (B), and facilitate a matrix resin (the thermoplastic resin (C)or (H)) to be impregnated into the carbon fibers (A) or the organicfibers (B) during molding, and facilitate the carbon fibers (A) or theorganic fibers (B) to be dispersed in the matrix resin (thethermoplastic resin (C) or (H)). In other words, the compound (D) andthe compound (I) serve as a so-called impregnation aid and a dispersionaid. As the compound (D) and the compound (I) may be the same type ofcompound, each other.

The carbon fiber reinforced molding material (X) has the composite (G)in which the carbon fibers (A) in the form of a continuous fiber bundleare present inside the thermoplastic resin (C), and the gaps between thesingle fibers of the carbon fibers (A) are filled with the compound (D).The composite (G) preferably has a structure in which the carbon fibers(A) are dispersed like islands in a sea of the compound (D). Likewise,it is preferred that the organic fiber reinforced molding material (Y)have the composite (J) in which the gaps between the single fibers ofthe organic fibers (B) are filled with the compound (I), and have astructure in which the organic fibers (B) are dispersed like islands ina sea of the compound (I).

The carbon fiber reinforced molding material (X) in the molding materialaccording to the second example preferably comprises the thermoplasticresin (C) at the outer side of the composite (G) obtained byimpregnating the carbon fibers (A) with the compound (D). A preferredstructure is one in which the thermoplastic resin (C) is disposed tosurround the composite (G) in a cross section perpendicular to thelonger direction of the carbon fiber reinforced molding material (X), orone in which the composite (G) and the thermoplastic resin (C) aredisposed in layers, the thermoplastic resin (C) being the outermostlayer in a cross section perpendicular to the longer direction of themolding material. Likewise, it is preferred that the organic fiberreinforced molding material (Y) comprise the thermoplastic resin (H) atthe outer side of the composite (J) obtained by impregnating the organicfibers (B) with the compound (I). A preferred structure is one in whichthe thermoplastic resin (H) is disposed to surround the composite (J) ina cross section perpendicular to the longer direction of the organicfiber reinforced molding material (Y), or one in which the composite (J)and the thermoplastic resin (H) are disposed in layers, thethermoplastic resin (H) being the outermost layer in a cross sectionperpendicular to the longer direction of the molding material.

In the molding material according to the second example, the compound(D) and the compound (I), in most cases, are low molecular weightcompounds, and are typically in the form of a solid that is relativelybrittle and easily broken, or a liquid, at normal temperature. In thecarbon fiber reinforced molding material (X) or the organic fiberreinforced molding material (Y), the structure in which thethermoplastic resin (C) or (H) is contained at the outer side of thecomposite (G) or the composite (J) allows the thermoplastic resin (C) or(H) having a high molecular weight to protect the composite (G) or thecomposite (J), to prevent the destruction, scattering and the like ofthe compound (D) or (I) due to impact, abrasion and the like duringconveyance and handling of the molding material, and to retain the shapeof the molding material. The molding material according to the secondexample preferably keeps the above-described shape until being subjectedto molding.

In the carbon fiber reinforced molding material (X), the composite (G)and the thermoplastic resin (C) may be such that the composite (G) andthe thermoplastic resin (C) which has partially penetrated into aportion of the composite (G) at or near their interface are mixing witheach other, or that the carbon fibers (A) are impregnated with thethermoplastic resin (C). And in the organic fiber reinforced moldingmaterial (Y), the composite (J) and the thermoplastic resin (H) may besuch that the composite (J) and the thermoplastic resin (H) which haspartially penetrated into a portion of the composite (J) at or neartheir interface are mixing with each other, or that the organic fibers(B) are impregnated with the thermoplastic resin (H).

The carbon fibers (A) in the carbon fiber reinforced molding material(X) preferably have a length that is substantially the same as thelength of the carbon fiber reinforced molding material (X). When thelength of the carbon fibers (A) is substantially the same as the lengthof the carbon fiber reinforced molding material (X), the resultingmolded article can contain the carbon fibers (A) having a long fiberlength, and thus can have excellent mechanical properties. The length ofthe carbon fiber reinforced molding material (X) refers to a lengththereof in the orientation direction of the carbon fibers (A) in thecarbon fiber reinforced molding material. Further, the expression“substantially the same length” means that the carbon fibers (A) are notcut intentionally in the molding material, or that the carbon fibers (A)significantly shorter than the overall length of the molding materialare substantially absent. Although the amount of the carbon fibers (A)shorter than the overall length of the molding material is not limitedto a particular value, the content of the carbon fibers (A) having alength that is 50% or less of the overall length of the molding materialis preferably 30% by mass or less, and more preferably 20% by mass orless, with respect to the total amount of the carbon fibers (A). Themolding material is preferably, but not necessarily, continuous and hasa cross-sectional shape that is substantially the same across the longerdirection. The length of the carbon fiber reinforced molding material(X) is typically 3 mm to 15 mm.

The organic fiber reinforced molding material (Y) comprises the organicfibers (B), the thermoplastic resin (H) and the compound (I), and mayhave a structure in which the thermoplastic resin (H) is contained atthe outer side of the composite (J) obtained by impregnating the organicfibers (B) with the compound (I), or may be in the form of pelletsobtained by melt-kneading the composite (J) and the thermoplastic resin(H).

In the molding material according to the second example, when theorganic fiber reinforced molding material (Y) is in the form of pelletsobtained by melt-kneading, the average fiber length of the organicfibers (B) is preferably 0.1 mm to 10 mm. When the average fiber lengthof the organic fibers (B) is within this range, the resulting moldedarticle can contain the organic fibers (B) having a long fiber length,and thus can have an improved impact strength. The average fiber lengthof the organic fibers (B) is more preferably 1.5 mm to 10 mm.

Further, when the organic fiber reinforced molding material (Y) has astructure in which the thermoplastic resin (H) is contained at the outerside of the composite (J) obtained by impregnating the organic fibers(B) with the compound (I), the organic fibers (B) preferably have alength that is substantially the same as the length of the organic fiberreinforced molding material (Y). When the length of the organic fibers(B) is substantially the same as the length of the organic fiberreinforced molding material (Y), the resulting molded article cancontain the organic fibers (B) having a long fiber length, and thus canhave excellent mechanical properties. The length of the organic fiberreinforced molding material (Y) refers to a length thereof in theorientation direction of the organic fibers (B) in the organic fiberreinforced molding material. Further, the expression “substantially thesame length” means that the organic fibers (B) are not cut intentionallyin the molding material, or that the organic fibers (B) significantlyshorter than the overall length of the molding material aresubstantially absent. More specifically, it means that the distancebetween two edges in the longer direction of the organic fibers (B) inthe organic fiber reinforced molding material (Y) is the same as thelength of the organic fiber reinforced molding material (Y) in thelonger direction. The content of the organic fibers (B) having a lengththat is 50% or less of the overall length of the molding material ispreferably 30% by mass or less, and more preferably 20% by mass or less,with respect to the total amount of organic fibers (B). The moldingmaterial is preferably, but not necessarily, continuous and has across-sectional shape that is substantially the same across the longerdirection. The length of the organic fiber reinforced molding material(Y) is typically 3 mm to 15 mm.

The “average fiber length” as used in the molding material can bedetermined in the same manner as the average fiber length in the moldedarticle.

As the components (A) to (D) of the molding material according to thesecond example, it is possible to use the components (A) to (D)described above in the section of the molded article. As the components(H) and (I), the components (C) and (D) described above in the sectionof the molded article can be used, respectively. In addition, the othercomponents exemplified for the molded article can be contained.

In the molding material according to the second example, the carbonfiber reinforced molding material (X) contains the carbon fibers (A) inan amount of 5 to 45 parts by weight (5 parts by weight or more and 45parts by weight or less), based on 100 parts by weight of the totalamount of the carbon fibers (A), the thermoplastic resin (C), and thecompound (D). To further improve the flexural properties and the impactstrength of the molded article, the content of the carbon fibers (A) ismore preferably 10 parts by weight or more. On the other hand, toimprove the dispersibility of the carbon fibers (A) in the moldedarticle and further improve the impact strength of the molded article,the content of the carbon fibers (A) is more preferably 30 parts byweight or less. Further, the carbon fiber reinforced molding material(X) contains the thermoplastic resin (C) in an amount of 35 to 94 partsby weight (35 parts by weight or more and 94 parts by weight or less).The content of the thermoplastic resin (C) is preferably 20 parts byweight or more, and more preferably 30 parts by weight or more. Tofurther improve the impact strength of the molded article, the contentof the thermoplastic resin (C) is preferably 85 parts by weight or less,and more preferably 75 parts by weight or less.

The compound (D) is preferably contained in an amount of 1 to 25 partsby weight (1 part by weight or more and 25 parts by weight or less). Toimprove the flowability and dispersibility of the carbon fibers (A) andthe organic fibers (B) during molding, the content of the compound (D)is more preferably 2 parts by weight or more, and still more preferably4 parts by weight or more. On the other hand, to further improve theflexural strength, tensile strength and impact strength of the moldedarticle, the content of the compound (D) is more preferably 20 parts byweight or less, and still more preferably 15 parts by weight or less.

The organic fiber reinforced molding material (Y) contains the organicfibers (B) in an amount of 1 to 45 parts by weight (1 part by weight ormore and 45 parts by weight or less) based on 100 parts by weight of theorganic fibers (B), thermoplastic resin (H) and the compound (I). Tofurther improve the impact properties of the molded article, the contentof the organic fibers (B) is preferably 5 parts by weight or more. Toimprove the dispersibility of the organic fibers (B) in the moldedarticle and further improve the impact strength of the molded article,the content of the organic fibers (B) is more preferably 30 parts byweight or less. Further, the organic fiber reinforced molding material(Y) contains the thermoplastic resin (H) in an amount of 35 to 94 partsby weight (35 parts by weight or more and 94 parts by weight or less).The content of the thermoplastic resin (H) is preferably 20 parts byweight or more, and more preferably 30 parts by weight or more. Tofurther improve the impact strength of the molded article, the contentof the thermoplastic resin (H) is preferably 85 parts by weight or less,and more preferably 75 parts by weight or less.

The compound (I) is contained in an amount of 1 to 25 parts by weight.To improve the flowability and dispersibility of the carbon fibers (A)and the organic fibers (B) during molding, the content of the compound(I) is more preferably 2 parts by weight or more, and still morepreferably 4 parts by weight or more. On the other hand, to furtherimprove the flexural strength, tensile strength, and impact strength ofthe molded article, the content of the compound (I) is more preferably20 parts by weight or less, and still more preferably 15 parts by weightor less.

The carbon fiber reinforced molding material (X) in the molding materialaccording to the second example can be obtained, for example, by thefollowing method. First, a roving of carbon fibers (A) is aligned in thelonger direction of fiber, and then the carbon fiber bundle isimpregnated with a molten compound (D) to prepare a composite (G). Thecomposite (G) is then guided to an impregnation die filled with a moltenthermoplastic resin (C) to coat the outer surface of the composite (G)with the thermoplastic resin (C), and pultruded through a nozzle. Thepultruded product is cooled and solidified, and then pelletized to apredetermined length to obtain a molding material. The thermoplasticresin (C) may be impregnated into the carbon fiber bundle as long as itis contained at the outer side of the composite (G). The organic fiberreinforced molding material (Y) in the molding material according to thesecond example may be produced, for example, by the same method as thatused for the above described carbon fiber reinforced molding material(X). Alternatively, the organic fiber reinforced molding material (Y)can be obtained, for example, by the following method. Specifically, anorganic fiber bundle is first impregnated with a molten compound (I) toprepare a composite (J); the composite (J) is melt-kneaded together witha thermoplastic resin (H) in a single- or twin-screw extruder and theresultant is discharged through a die tip into a strand; and the strandis cooled and solidified, and then pelletized to a predetermined lengthto obtain a molding material.

By mixing the carbon fiber reinforced molding material (X) and theorganic fiber reinforced molding material (Y), as components of themolding material according to the second example, by dry blending, andmolding the resulting mixture, it is possible to obtain a fiberreinforced thermoplastic resin molded article excellent indispersibility of the carbon fibers (A) and the organic fibers (B),impact strength, and low-temperature impact strength. As for the mixingratio of the carbon fiber reinforced molding material (X) to the organicfiber reinforced molding material (Y), the carbon fiber reinforcedmolding material (X) and the organic fiber reinforced molding material(Y) are preferably contained in an amount of 50 to 80 parts by weightand 20 to 50 parts by weight, respectively, based on 100 parts by weightof the total amount of the carbon fiber reinforced molding material (X)and the organic fiber reinforced molding material (Y). In addition, theuse of the organic fiber reinforced molding material (Y) produced bymelt-kneading allows for producing a fiber reinforced thermoplasticresin molded article with higher productivity. A preferred moldingmethod is one using a mold, and various known methods such as injectionmolding, extrusion molding, and press molding can be used. Inparticular, a molding method using an injection molding machine producesmolded articles continuously and stably.

The organic fibers (B) in the molding material according to the secondexample have a number average fiber diameter (d_(B)) of 35 to 300 μm (35μm or more and 300 μm or less). Since the number average fiber diameter(d_(B)) of the organic fibers (B) generally does not change before andafter the production process of the molding material, it is possible toeasily adjust the number average fiber diameter (d_(B)) of the organicfibers (B) in the molding material within the above described desiredrange, by adjusting the number average fiber diameter (d_(B)) of theorganic fibers (B) as a raw material to 35 to 300 The number averagefiber diameter (d_(B)) of the organic fibers (B) in the molding materialis more preferably 50 μm or more and 150 μm or less.

The “number average fiber diameter” of the organic fibers (B) refers toan average fiber diameter calculated according to the followingequation.Number average fiber diameter=Σ/(di×Ni)/Σ(Ni)

-   -   di: fiber diameter (μm)    -   Ni: number of organic fibers having a fiber diameter di

The number average fiber diameter of the organic fibers in the moldingmaterial can be determined in the same manner as the number averagefiber diameter of the organic fibers in the molded article.

Further, in the molding materials according to the first and the secondexamples, the organic fibers (B) preferably have an aspect ratio (L_(B)[μm]/d_(B) [μm]) of 10 to 500 (10 or more and 500 or less).

As described above regarding the aspect ratio of the organic fibers (B)in the molded article, examples of means of adjusting the aspect ratioin the above range include balancing the average fiber length and thenumber average fiber diameter. When the aspect ratio of the organicfibers (B) is adjusted to 10 or more, the load applied upon impact canbe transmitted to the organic fibers, thereby further improving theimpact strength of the molded article. The aspect ratio of the organicfibers (B) is more preferably 20 or more. On the other hand, when theaspect ratio of the organic fibers (B) is adjusted to 500 or less, it ispossible to inhibit generating the surface asperity of the moldedarticle due to the organic fibers (B), and a further improved surfaceappearance can be achieved.

The aspect ratio of the organic fibers (B) in the molding material canbe calculated from the average fiber diameter and the number averagefiber length of the organic fibers (B) present in the molding material.The number average fiber diameter of the organic fibers (B) in themolding material can be determined according to the above describedmethod. Further, the average fiber length of the organic fibers (B) inthe molding material can be measured according to the following method.A molding material is heated on a hot stage set at 300° C. in a statesandwiched between glass plates, to form a film in which fibers areuniformly dispersed. The film in which organic fibers are uniformlydispersed is observed under a light microscope (at 50 to 200×). Thefiber lengths of randomly selected 1,000 organic fibers (B) aremeasured, and the average fiber length (L_(B)) is calculated accordingto the following equation.Average fiber length=Σ(Mi ² ×Ni)/Σ(Mi×Ni)

-   -   Mi: fiber length (mm)    -   Ni: number of organic fibers having a fiber length Mi

The aspect ratio of the organic fibers (B) in the molding material canbe adjusted within the above described preferred range, for example, byadjusting the average fiber length and the number average fiber diameterof the organic fibers (B) in the molding material within the abovedescribed preferred ranges.

A method of producing the molding material will now be described.

The molding material according to the first example can be obtained, forexample, by the following method. First, a roving of carbon fibers (A)and a roving of organic fibers (B) are doubled in parallel to the longerdirection of fiber to prepare a fiber bundle (E) including the carbonfibers (A) and the organic fibers (B). The fiber bundle (E) is thenimpregnated with a molten compound (D) to prepare a composite (F). Thecomposite (F) is guided to an impregnation die filled with a moltenthermoplastic resin (C) to coat the outer surface of the composite (F)with the thermoplastic resin (C), and pultruded through a nozzle. Thepultruded product is cooled and solidified, and then pelletized to apredetermined length to obtain a molding material. The thermoplasticresin (C) may be impregnated into the fiber bundle (E) as long as it iscontained at the outer side of the composite (F). Further, the moldingmaterial according to the second example can be obtained, for example,by the following method. First, a roving of carbon fibers (A) is drawnin the longer direction of fiber, and then the roving of the carbonfibers (A) is impregnated with a molten compound (D) to prepare acomposite (G). The composite (G) is then guided to an impregnation diefilled with a molten thermoplastic resin (C) to coat the outer surfaceof the composite (G) with the thermoplastic resin (C), and pultrudedthrough a nozzle. The pultruded product is cooled and solidified, andthen pelletized to a predetermined length to obtain a carbon fiberreinforced molding material (X). Further, a roving of organic fibers (B)having a number average fiber diameter (d_(B)) of 35 to 300 μm is drawnin the longer direction of fiber, and then the roving of the organicfibers (B) is impregnated with a molten compound (I) to prepare acomposite (J). The composite (J) is then guided to an impregnation diefilled with a molten thermoplastic resin (H) to coat the outer surfaceof the composite (J) with the thermoplastic resin (H), and pultrudedthrough a nozzle. The pultruded product is cooled and solidified, andthen pelletized to a predetermined length to obtain an organic fiberreinforced molding material (Y). Alternatively, an organic fiber bundleis impregnated with a molten compound (I) to prepare a composite (J);the composite (J) is melt-kneaded together with a thermoplastic resin(H) in a single- or twin-screw extruder, and the resultant is dischargedthrough a die tip into a strand; and the strand is cooled andsolidified, and then pelletized to a predetermined length to obtain anorganic fiber reinforced molding material (Y). Then, the thus producedtwo types of molding materials, namely, the organic fiber reinforcedmolding materials (X) and (Y), are dry blended to obtain a moldingmaterial. The thermoplastic resin (C) or (H) may be impregnated into theroving of the carbon fibers (A) or the roving of the organic fibers (B),as long as the thermoplastic resin (C) or (H) is contained at the outerside of the roving of the carbon fibers (A) or the roving of the organicfibers (B).

The molded article is a fiber reinforced thermoplastic resin moldedarticle excellent in impact strength. The molded article is suitablyused, for example, for: automotive parts such as instrument panels, doorbeams, underside covers, lamp housings, pedal housings, radiatorsupports, spare tire covers, and various modules at a front end and thelike; parts of home and office electrical appliances such as telephones,facsimiles, VTRs, copying machines, televisions, microwave ovens, audioequipment, toiletry goods, “LASER DISC (registered trademark)”,refrigerators, and air-conditioners; and members for use in electricaland electronic equipment, represented by housings used for personalcomputers and cellular phones, and keyboard supports for supporting akeyboard in a personal computer. Among these, the molded article ispreferably used for parts such as instrument panels, housings used forelectrical and electronic equipment as applications in which goodappearance is required in many cases and impact strength is also deemedimportant.

EXAMPLES

Our molding materials and molded articles will now be described in moredetail with reference to Examples, but these examples are not intendedto limit this disclosure in any way. First, methods of evaluatingvarious properties used in the Examples will be described.

(1) Measurement of Melt Viscosity

For each of the thermoplastic resins (C) and (H) and the compounds (D)and (I) used in Examples and Comparative Examples, the melt viscosity at200° C. was measured with a viscoelasticity meter at 0.5 Hz using a40-mm parallel plate.

(2) Measurement of Average Fiber Lengths of Carbon Fibers (A) andOrganic Fibers (B) in Molded Article and Molding Material

A molded article or a molding material was heated on a hot stage set at300° C. in a state sandwiched between glass plates, to form a film inwhich fibers were uniformly dispersed. The film in which the carbonfibers (A) or the organic fibers (B) were uniformly dispersed wasobserved under a light microscope (at 50 to 200×). The fiber lengths ofrandomly selected 1,000 carbon fibers (A) and randomly selected 1,000organic fibers (B) were measured, and the average fiber length of eachtype of the fibers was calculated according to the following equation.Average fiber length=Σ(Mi ² ×Ni)/Σ(Mi×Ni)

-   -   Mi: fiber length (mm)    -   Ni: number of fibers having a fiber length Mi        (3) Measurement of Number Average Fiber Diameters of Carbon        Fibers (A) and Organic Fibers (B) in Molded Article and Molding        Material

A molded article or a molding material was heated on a hot stage set at300° C. in a state sandwiched between glass plates, to form a film inwhich fibers were uniformly dispersed. The film in which the carbonfibers (A) or the organic fibers (B) were uniformly dispersed wasobserved under a light microscope (at 5 to 1,000×). The fiber diametersof randomly selected 10 carbon fibers (A) or organic fibers (B) weremeasured, and the number average fiber diameter was calculated accordingto the following equation. The fiber diameter of a single fiber of thecarbon fibers (A) or the organic fibers (B) as used herein refers to, asshown in FIG. 4, the shortest distance (6) between the arbitrary point Bon the fiber contour A (4) and the fiber contour A′ (5) opposite to thefiber contour A (4), in each carbon fiber (A) or organic fiber (B) to beobserved. A number average value obtained by: measuring the fiberdiameter at randomly selected 20 locations per one piece of carbon fiber(A) or organic fiber (B); and calculating the average of the measuredvalues at the total 200 locations, was defined as the number averagefiber diameter. When the number of the carbon fibers (A) or the organicfibers (B) present within an observation area was less than 10 pieces,the observation area was moved as appropriate to a new area in which 10pieces of the carbon fibers (A) or the organic fibers (B) could beobserved.Number average fiber diameter=Σ/(di×Ni)/Σ(Ni)

-   -   di: fiber diameter (μm)    -   Ni: number of fibers having a fiber diameter di        (4) Measurement of Ratio (n_(B)/n_(A)) of Calculated Number of        Organic Fibers (B) to Calculated Number of Carbon Fibers (A) in        Molded Article

The carbon fibers (A) and the organic fibers (B) were retrieved from anISO-type dumbbell test specimen obtained in each of Examples andComparative Examples, and the specific gravity of each type of fiberswas measured using a liquid immersion method. The carbon fibers wereretrieved by subjecting the test specimen to a heat treatment under anitrogen atmosphere at 500° C. for 30 minutes. The organic fibers (B)were retrieved by dissolving the test specimen in 1-chloronaphthalene toretrieve the carbon fibers (A) and the organic fibers (B), and thenintroducing the retrieved fibers into chloroform to allow the carbonfibers (A) to settle down, and the organic fibers (B) to float, therebyseparating the fibers. Using distilled water as a liquid to be used inthe liquid immersion method, the measurement of the specific gravity wascarried out on 5 pieces of test specimens, and the average value thereofwas calculated. The calculated number of fibers was calculated from thenumber average fiber diameter d (μm), average fiber length L (mm), fibercontent w (% by mass), and specific gravity ρ (g/cm³) of each type offibers, obtained by the methods described above, according to thefollowing equation.Calculated number of fibers=((1×w/100)/((d/2)² ×π×L×ρ))×10⁹(5) Measurement of Tensile Break Elongation

The tensile break elongation (%) of the organic fibers (B) was measuredas follows: a tensile test was carried out in a room under standardconditions (20° C., 65% RH) at a chuck distance of 250 mm and a tensilespeed of 300 mm/min, and the length at fiber break was measured(breakages in the vicinity of chucks were considered as a chuckingbreakage and excluded from the resulting data), calculated to the seconddecimal place by the following equation, and rounded to one decimalplace. The average value of the measured values (number of data: n=3)was calculated, for each organic fibers (B), and defined as the tensilebreak elongation.Tensile break elongation (%)=[(length at break (mm)−250)/250]×100(6) Measurement of Flexural Strength of Molded Article

For each of the ISO dumbbell specimens obtained in Examples andComparative Examples, the flexural strength was measured in accordancewith ISO 178, using a 3-point bend fixture (indenter radius: 5 mm) at afulcrum distance of 64 mm, under test conditions of a testing speed of 2mm/min. “INSTRON” (registered trademark) universal tester model 5566(manufactured by Instron) was used as a tester.

(7) Measurement of Charpy Impact Strength of Molded Article

A parallel portion of each of the ISO dumbbell specimens obtained inExamples and Comparative Examples was cut out, and a V-notch Charpyimpact test was performed in accordance with ISO179, using a C1-4-01model tester manufactured by Tokyo Testing Machine Inc. to calculate theimpact strength (kJ/cm²).

(8) Evaluation of Productivity of Molding Material

The production volume of the organic fiber reinforced molding material(Y) per hour was determined. Those produced at a production volume of 10kg/hr or more were evaluated as A, and those produced at a productionvolume of less than 10 kg/hr were evaluated as B.

(9) Evaluation of Fiber Dispersibility in Molded Article Obtained UsingMolding Material

For each of the specimens of 80 mm×80 mm×2 mm obtained in Examples andComparative Examples, the number of undispersed carbon fiber bundlesexisting on the front and back surfaces was visually counted. The fiberdispersibility was evaluated based on the total sum of the number ofundispersed carbon fiber bundles on 50 molded articles, according to thefollowing criteria. Those evaluated as A and B were regarded asacceptable.

A: Less than 1 undispersed carbon fiber bundle

B: Not less than 1 and less than 5 undispersed carbon fiber bundles

C: Not less than 5 and less than 10 undispersed carbon fiber bundles

D: 10 or more undispersed carbon fiber bundles

(10) Evaluation of Painted Surface Appearance

Each of the specimens of 80 mm×80 mm×2 mm obtained in Examples andComparative Examples was painted with acryl-urethane two-pack paint(Urethane PG60/hardener, manufactured by Kansai Paint Co., Ltd.) so thatthe paint thickness was 30 μm, by using paint robot (KE610H,manufactured by Kawasaki Heavy Industries, Ltd.) and cartridge bellmanufactured by ABB K.K. and each painted specimen was dried at dryingtemperature 80° C. for 30 min. The painted surface appearance wasvisually evaluated based on definition and appearance of the obtainedpainted molded articles, according to the following criteria. Thoseevaluated as A and B were regarded as acceptable and C and D wereregarded as inacceptable.

A: High sense of glossiness was observed

B: Sense of glossiness was observed but not so high sense of glossiness

C: Partial uneven paint was observed

D: Uneven paint was observed overall

Reference Example 1 Preparation of Carbon Fibers (A)

A copolymer comprising polyacrylonitrile as a major component wassubjected to spinning, firing, and surface oxidation to obtaincontinuous carbon fibers with a total fiber count of 24,000, a singlefiber diameter of 7 μm, a mass per unit length of 1.6 g/m, a specificgravity of 1.8 g/cm³, and a surface oxygen concentration ratio [O/C] of0.2. These continuous carbon fibers had a strand tensile strength of4,880 MPa and a strand tensile modulus of 225 GPa. Subsequently, amother liquor of a sizing agent was prepared by dissolving polyglycerolpolyglycidyl ether as a polyfunctional compound in water to aconcentration of 2% by weight, and the resulting sizing agent wasapplied to the carbon fibers by a dipping method and dried at 230° C.The amount of sizing agent deposited on the carbon fibers thus obtainedwas 1.0% by weight.

Reference Example 2 Organic Fibers (B)

Polyester (PET) fibers 1: “TETORON” (registered trademark) 56T-36-262manufactured by Toray Industries, Inc. (single fiber fineness: 1.6 dtex,fiber diameter: 12 μm, melting point: 260° C.) were used. The elongationat break of the fibers was measured by the method described in (5) aboveto be 15%.

Polyester fibers 2: “TETORON” (registered trademark) 2200T-480-705Mmanufactured by Toray Industries, Inc. (single fiber fineness: 4.6 dtex,fiber diameter: 20 μm, melting point: 260° C.) were used. The elongationat break of the fibers was measured by the method described in (5) aboveto be 15%.

Polyester (PET) fibers 3: Dried PET pellets (PET pellets) havingviscosity [η] of 0.94 and COOH terminal group concentration of 13 eq/10⁶g, produced by publicly known melt polycondensation and solid-phasepolycondensation, were continuously supplied to a single-screw extruderthrough hopper of the single-screw extruder while metering. At the sametime, heat melted “STABILIZER” (registered trademark) 7000 (manufacturedby Raschig AG) at 80° C. as a monocarbodiimide compound (TIC) wascontinuously supplied while metering at the weight ratio of 1.3 parts byweight to 100 parts by weight of the above PET pellets in a pipe set atthe bottom of the hopper. Melted polymer melt-kneaded at about 288° C.for 3 min in the single-screw extruder passed through a gear pump, afilter layer in spinning pack and was discharged from a spinning orificefor fibers having circular cross section. The spun filaments were cooledin water bath of 70° C. and then stretching and heat set wereconventionally executed at the total stretching ratio of 5.0 times, toobtain polyester fibers having circular cross section of 35 μm diameter(single fiber fineness: 13 dtex, fiber diameter: 35 μm, melting point:260° C.). The elongation at break of the fibers was measured by themethod described in (5) above to be 15%.

Polyester (PET) fibers 4: Polyester fibers having circular cross sectionof 50 μm diameter (single fiber fineness: 27 dtex, fiber diameter: 50μm, melting point: 260° C.) were obtained in the same manner as PETfibers 3 above, except for changing the size of spinning orifice forfibers having circular cross section. The elongation at break of thefibers was measured by the method described in (5) above to be 15%.

Polyester (PET) fibers 5: Polyester fibers having circular cross sectionof 100 μm diameter (single fiber fineness: 108 dtex, fiber diameter: 100μm, melting point: 260° C.) were obtained in the same manner as PETfibers 3 above, except for changing size of spinning orifice for fibershaving circular cross section. The elongation at break of the fibers wasmeasured by the method described in (5) above to be 15%.

Polyester (PET) fibers 6: Polyester fibers having circular cross sectionof 290 μm diameter (single fiber fineness: 975 dtex, fiber diameter: 290μm, melting point: 260° C.) were obtained in the same manner as PETfibers 3 above, except for changing size of spinning orifice for fibershaving circular cross section. The elongation at break of the fibers wasmeasured by the method described in (5) above to be 15%.

Reference Example 3 Thermoplastic Resins (C) and (H)

A pellet blend of PP: a polypropylene resin (“PRIME POLYPRO” (registeredtrademark) J137 manufactured by Prime Polymer Co., Ltd.) and a maleicacid-modified polypropylene resin (“ADMER” (registered trademark) QE840manufactured by Mitsui Chemicals, Inc.) (PP), blended at a weight ratioof 85/15, was used. The melt viscosity at 200° C. was measured by themethod described in (1) above to be 50 Pa·s.

PC: a polycarbonate resin (“PANLITE” (registered trademark) L-1225Lmanufactured by Idemitsu Kosan Co., Ltd.) was used. In the same manneras in the above described polypropylene resin, the melt viscosity at200° C. was measured by the method described in (1) above to be 14,000Pa·s.

Reference Example 4 Compounds (D) and (I)

A solid hydrogenated terpene resin (“CLEARON” (registered trademark)P125 manufactured by Yasuhara Chemical Co., Ltd., softening point: 125°C.) was used. The above resin was introduced into a tank in animpregnation aid applicator. The temperature in the tank was set at 200°C., and the resin was heated for 1 hour to a molten state. The meltviscosity at 200° C. of the resulting resin at this time was measured bythe method described in (1) above to be 1 Pa·s.

Production Example 1 Carbon Fiber Reinforced Thermoplastic Resin MoldingMaterial (X-1)

A composite (G) obtained by impregnating a bundle of the carbon fibers(A) described above with the compound (D) at the ratio shown in Table 1was passed through a coating die for wire coating mounted at the end ofa TEX-30α model twin-screw extruder (screw diameter: 30 mm, L/D=32)manufactured by Japan Steel Works, LTD. Meanwhile, the thermoplasticresin (C) shown in Table 1 was supplied from a main hopper of theTEX-30α model twin-screw extruder and melt-kneaded at a screw speed of200 rpm. The molten thermoplastic resin (C) was discharged from thetwin-screw extruder into the die such that the molten thermoplasticresin (C) was disposed continuously surrounding the composite (G). Theresulting strand was cooled and then cut with a cutter into pellets witha length of 7 mm to provide long-fiber pellets (X-1) in which the lengthof the bundle of the carbon fibers (A) and the length of the moldingmaterial are substantially the same. The take-up speed of the bundle ofthe carbon fibers (A) was adjusted such that the amount of the carbonfibers (A) was 30 parts by weight based on 100 parts by weight of thetotal amount of (A), (C), and (D).

Production Example 2 Carbon Fiber Reinforced Thermoplastic Resin MoldingMaterial (X-2)

Long-fiber pellets (X-2) were prepared in the same manner as inProduction Example 1 above. The take-up speed of the bundle of thecarbon fibers (A) was adjusted such that the amount of the carbon fibers(A) was 40 parts by weight based on 100 parts by weight of the totalamount of (A), (C), and (D).

Production Example 3 Organic Fiber Reinforced Thermoplastic ResinMolding Material (Y-1)

A composite (J) obtained by impregnating a bundle of the organic fibers(B) described above with the compound (I) at the ratio shown in Table 1was passed through a coating die for wire coating mounted at the end ofa TEX-30α model twin-screw extruder (screw diameter: 30 mm, L/D=32)manufactured by Japan Steel Works, LTD. Meanwhile, the thermoplasticresin (H) shown in Table 1 was supplied from a main hopper of theTEX-30α model twin-screw extruder and melt-kneaded at a screw speed of200 rpm. The molten thermoplastic resin (H) was discharged from thetwin-screw extruder into the die such that the molten thermoplasticresin (H) was disposed continuously surrounding the composite (J). Theresulting strand was cooled and then cut with a cutter into pellets witha length of 7 mm to provide long-fiber pellets (Y-1) in which the lengthof the bundle of the organic fibers (B) and the length of the moldingmaterial are substantially the same. The take-up speed of the bundle ofthe organic fibers (B) was adjusted such that the amount of the organicfibers (B) was 30 parts by weight based on 100 parts by weight of thetotal amount of (B), (H), and (I).

Production Example 4 Organic Fiber Reinforced Thermoplastic ResinMolding Material (Y-2)

Long-fiber pellets (Y-2) were prepared in the same manner as inProduction Example 3 above. The take-up speed of the bundle of theorganic fibers (B) was adjusted such that the amount of the organicfibers (B) was 40 parts by weight based on 100 parts by weight of thetotal amount of (B), (H), and (I).

Production Example 5 Organic Fiber Reinforced Thermoplastic ResinMolding Material (Y-3)

Long-fiber pellets (Y-3) were prepared in the same manner as inProduction Example 3 above. The take-up speed of the bundle of theorganic fibers (B) was adjusted such that the amount of the organicfibers (B) was 50 parts by weight based on 100 parts by weight of thetotal amount of (B), (H), and (I).

Production Example 6 Organic Fiber Reinforced Thermoplastic ResinMolding Material (Y-4)

A composite (J) obtained by impregnating a bundle of the organic fibers(B) described above with the compound (I) at the ratio shown in Table 1was melt-kneaded in a cylinder at a screw speed of 200 rpm together withthe thermoplastic resin (H) molten in a TEX-30α model twin-screwextruder (screw diameter: 30 mm, L/D=32) manufactured by Japan SteelWorks, LTD. The strand discharged through a die tip was cooled andsolidified, and then cut with a cutter into pellets with a length of 7mm to prepare pellets (Y-4). The take-up speed of the bundle of theorganic fibers (B) was adjusted such that the amount of the organicfibers (B) was 30 parts by weight based on 100 parts by weight of thetotal amount of (B), (H), and (I).

Example 1

An apparatus for producing long-fiber reinforced resin pellets, theapparatus including a coating die for wire coating mounted at the end ofa TEX-30α model twin-screw extruder (screw diameter: 30 mm, L/D=32)manufactured by Japan Steel Works, LTD., was used. The cylindertemperature of the extruder was set at 220° C., and the thermoplasticresin (C) shown in Table 2 was supplied from a main hopper of theapparatus, and melt-kneaded at a screw speed of 200 rpm. While adjustingthe discharge rate such that the amount of the compound (D) which hadbeen melted by heating at 200° C. to be 8 parts by weight based on 100parts by weight of the total amount of the components (A) to (C), afiber bundle (E) composed of the carbon fibers (A) and the organicfibers (B) was supplied at a die port (3 mm in diameter) from which themolten thermoplastic resin (C) is discharged so that the thermoplasticresin (C) was disposed continuously surrounding the bundle. In aninternal cross section of the fiber bundle (E) at this time, the carbonfibers (A) and the organic fibers (B) were unevenly distributed. Theywere unevenly distributed such that at least a portion of the carbonfibers (A) and at least a portion of the organic fibers (B) were incontact with the thermoplastic resin (C). The resulting strand wascooled and then cut with a cutter into pellets with a length of 7 mm toobtain long-fiber pellets. The take-up speed was adjusted such that theamount of the carbon fibers (A) was 20 parts by weight, and the amountof the organic fibers (B) was 10 parts by weight based on 100 parts byweight of the total amount of the components (A) to (C).

The long-fiber pellets thus obtained were injection molded using aninjection molding machine J110AD manufactured by Japan Steel Works, LTD.under the conditions of: an injection time of 5 seconds; a back pressureof 5 MPa; a holding pressure of 20 MPa; a pressure holding time of 10seconds; a cylinder temperature of 230° C.; and a mold temperature of60° C., to prepare an ISO dumbbell specimen and a specimen of 80 mm×80mm×2 mm, as molded articles. The cylinder temperature as used aboverefers to the temperature of a portion for heating and melting a moldingmaterial in the injection molding machine, and the mold temperaturerefers to the temperature of a mold into which a resin is injected to beformed into a desired shape. The properties of the resulting specimens(molded articles) were evaluated after allowing them to stand in aconstant temperature and humidity room conditioned at 23° C. and 50% RHfor 24 hours. The evaluation was carried out according to the methodsdescribed above, and the results are summarized in Table 2.

Example 2

Molded articles were prepared and evaluated in the same manner as inExample 1 except that the polyester (PET) fibers 4 were used as theorganic fibers (B). The evaluation results are summarized in Table 2.

Example 3

Molded articles were prepared and evaluated in the same manner as inExample 1, except that the polyester (PET) fibers 5 were used as theorganic fibers (B). The evaluation results are summarized in Table 2.

Example 4

Molded articles were prepared and evaluated in the same manner as inExample 1 except that the polyester (PET) fibers 6 were used as theorganic fibers (B). The evaluation results are summarized in Table 2.

Example 5

Long-fiber pellets were prepared and evaluated in the same manner as inExample 3 except that the injection time was set at three seconds andback pressure was set at 10 MPa in the injection conditions. Theevaluation results are summarized in Table 2.

Example 6

Long-fiber pellets were prepared and evaluated in the same manner as inExample 2 except that the amounts of the carbon fibers (A), thethermoplastic resin (C), and the compound (D) were 30 parts by weight,60 parts by weight, and 11 parts by weight, respectively, based on 100parts by weight of the total amount of the components (A) to (C). Theevaluation results are summarized in Table 3.

Example 7

Long-fiber pellets were prepared and evaluated in the same manner as inExample 2 except that the amounts of the organic fibers (B), thethermoplastic resin (C), and the compound (D) were 30 parts by weight,50 parts by weight, and 14 parts by weight, respectively, based on 100parts by weight of the total amount of the components (A) to (C). Theevaluation results are summarized in Table 3.

Example 8

Long-fiber pellets were prepared and evaluated in the same manner as inExample 2 except that the carbon fibers (A) and the organic fibers (B)were disposed in the fiber bundle (E) such that the carbon fibers (A)envelop the organic fibers (B). The evaluation results are summarized inTable 3.

Example 9

Long-fiber pellets were prepared and evaluated in the same manner as inExample 1 except that the carbon fibers (A) and the organic fibers (B)were disposed in the fiber bundle (E) such that the organic fibers (B)envelop the carbon fibers (A). The evaluation results are summarized inTable 3.

Example 10

The long-fiber pellets (X-1) obtained in Production Example 1 and thelong-fiber pellets (Y-1) obtained in Production Example 3 were dryblended such that the amounts of (X-1) and (Y-1) were 67 parts by weightand 33 parts by weight, respectively, based on 100 parts by weight ofthe total amount of (X-1) and (Y-1), to prepare a molding material. Inthe resulting molding material, as a whole, the amounts of the carbonfibers (A), the organic fibers (B), the thermoplastic resin (C), and thecompound (D) were 22 parts by weight, 12 parts by weight, 66 parts byweight, and 9 parts by weight, respectively, based on 100 parts byweight of the total amount of the carbon fibers (A), organic fibers (B),and the thermoplastic resin (C). This molding material was evaluatedaccording to the methods described above, and the results are summarizedin Table 4.

Example 11

A molding material was prepared and evaluated in the same manner as inExample 9 except that the long-fiber pellets (X-1) obtained inProduction Example 1, the long-fiber pellets (Y-2) obtained inProduction Example 4, and pellets of the thermoplastic resin (C) shownin Table 4 were dry blended such that the amounts of (X-1), (Y-2), and(C) were 17 parts by weight, 75 parts by weight, and 8 parts by weight,respectively. In the resulting molding material, as a whole, the amountsof the carbon fibers (A), the organic fibers (B), the thermoplasticresin (C), and the compound (D) were 6 parts by weight, 33 parts byweight, 61 parts by weight, and 10 parts by weight, respectively, basedon 100 parts by weight of the total amount of the carbon fibers (A),organic fibers (B), and the thermoplastic resin (C). The evaluationresults of this molding material are summarized in Table 4.

Example 12

A molding material was prepared and evaluated in the same manner as inExample 9 except that the long-fiber pellets (X-2) obtained inProduction Example 2 and the long-fiber pellets (Y-2) obtained inProduction Example 4 were dry blended such that the amounts of (X-2) and(Y-2) were 75 parts by weight and 25 parts by weight, respectively,based on 100 parts by weight of the total amount of (X-2) and (Y-2). Inthe resulting molding material, as a whole, the amounts of the carbonfibers (A), the organic fibers (B), the thermoplastic resin (C), and thecompound (D) were 33 parts by weight, 11 parts by weight, 56 parts byweight, and 11 parts by weight, respectively, based on 100 parts byweight of the total amount of the carbon fibers (A), organic fibers (B),and the thermoplastic resin (C). The evaluation results of this moldingmaterial are summarized in Table 4.

Example 13

A molding material was prepared and evaluated in the same manner as inExample 10 except that the pellets (Y-4) obtained in Production Example6 were used in place of the long-fiber pellets (Y-1). In the resultingmolding material, as a whole, the amounts of the carbon fibers (A), theorganic fibers (B), the thermoplastic resin (C), and the compound (D)were 22 parts by weight, 11 parts by weight, 67 parts by weight, and 9parts by weight, respectively, based on 100 parts by weight of the totalamount of the carbon fibers (A), organic fibers (B), and thethermoplastic resin (C). The evaluation results of this molding materialare summarized in Table 4.

Comparative Example 1

Molded articles were prepared and evaluated in the same manner as inExample 1 except that the PET fibers 2 were used as the organic fibers(B). The evaluation results are summarized in Table 5.

Comparative Example 2

Molded articles were prepared and evaluated in the same manner as inExample 1 except that the amounts of the carbon fibers (A), thethermoplastic resin (C), and the compound (D) were 3 parts by weight, 87parts by weight, and 6 parts by weight, respectively, based on 100 partsby weight of the total amount of the components (A) to (C). Theevaluation results are summarized in Table 5.

Comparative Example 3

Molded articles were prepared and evaluated in the same manner as inExample 1 except that the amounts of the carbon fibers (A), thethermoplastic resin (C), and the compound (D) were 50 parts by weight,40 parts by weight, and 14 parts by weight, respectively, based on 100parts by weight of the total amount of the components (A) to (C). Theevaluation results are summarized in Table 5.

Comparative Example 4

Molded articles were prepared and evaluated in the same manner as inExample 1 except that the amounts of the organic fibers (B), thethermoplastic resin (C), and the compound (D) were 50 parts by weight,30 parts by weight, and 16 parts by weight, respectively, based on 100parts by weight of the total amount of (A) to (C). The evaluationresults are summarized in Table 5.

Comparative Example 5

Molded articles were prepared and evaluated in the same manner as inExample 1 except that the back pressure in injection molding wasadjusted to 13 MPa. The evaluation results are summarized in Table 5.

Comparative Example 6

Molded articles were prepared and evaluated in the same manner as inExample 1 except that the injection time in injection molding wasadjusted to 0.5 seconds, and the back pressure was adjusted to 15 MPa.The evaluation results are summarized in Table 5.

Comparative Example 7

Molded articles were prepared and evaluated in the same manner as inExample 1 except that the PET fibers 1 were used as the organic fibers(B). The evaluation results are summarized in Table 5.

Comparative Example 8

Long-fiber pellets were prepared and evaluated in the same manner as inExample 1 except that the amounts of the carbon fibers (A), the organicfibers (B), the thermoplastic resin (C), and the compound (D) were 3parts by weight, 20 parts by weight, 77 parts by weight, and 8 parts byweight, respectively, based on 100 parts by weight of the total amountof the components (A) to (D). The evaluation results are summarized inTable 6.

Comparative Example 9

Long-fiber pellets were prepared and evaluated in the same manner as inExample 1 except that the amounts of the carbon fibers (A), the organicfibers (B), the thermoplastic resin (C), and the compound (D) were 10parts by weight, 50 parts by weight, 40 parts by weight, and 16 parts byweight, respectively, based on 100 parts by weight of the total amountof the components (A) to (C). The evaluation results are summarized inTable 5.

Comparative Example 10

Long-fiber pellets were prepared and evaluated in the same manner as inExample 1 except that the carbon fibers (A) and the organic fibers (B)were disposed in an internal cross section of the fiber bundle (E) inthe form that was mixed uniformly. The evaluation results are summarizedin Table 6.

Comparative Example 11

A molding material was prepared and evaluated in the same manner as inExample 7 except that the long-fiber pellets (X-1) obtained inProduction Example 1 and pellets of the thermoplastic resin (C) shown inTable 7 were dry blended such that the amounts of (X-1) and (C) were 67parts by weight and 33 parts by weight, respectively, based on 100 partsby weight of the total amount of (X-1) and (C). In the resulting moldingmaterial, as a whole, the amounts of the carbon fibers (A), the organicfibers (B), the thermoplastic resin (C), and the compound (D) were 20parts by weight, 0 parts by weight, 80 parts by weight, and 5 parts byweight, respectively, based on 100 parts by weight of the total amountof the carbon fibers (A), organic fibers (B), and the thermoplasticresin (C). The evaluation results of this molding material aresummarized in Table 7.

Comparative Example 12

A molding material was prepared and evaluated in the same manner as inExample 7 except that the long-fiber pellets (X-1) obtained inProduction Example 1, the long-fiber pellets (Y-3) obtained inProduction Example 5, and pellets of the thermoplastic resin (C) shownin Table 7 were dry blended such that the amounts of (X-1), (Y-3), and(C) were 10 parts by weight, 20 parts by weight, and 70 parts by weight,respectively, based on 100 parts by weight of the total amount of (X-1),(Y-3), and (C). In the resulting molding material, as a whole, theamounts of the carbon fibers (A), the organic fibers (B), thethermoplastic resin (C), and the compound (D) were 3 parts by weight, 11parts by weight, 86 parts by weight, and 3 parts by weight,respectively, based on 100 parts by weight of the total amount of thecarbon fibers (A), organic fibers (B), and the thermoplastic resin (C).The evaluation results of this molding material are summarized in Table7.

TABLE 1 Manufac- Manufac- Manufac- Manufac- Manufac- Manufac- turingturing turing turing turing turing Example 1 Example 2 Example 3 Example4 Example 5 Example 6 X-1 X-2 Y-1 Y-2 Y-3 Y-4 Raw Carbon Fibers (A)Amount Parts by 30 40 — — — — Materials Weight Thermoplastic Resin Type— PP PP — — — — (C) Amount Parts by 62 50 — — — — Weight Compound (D)Type — Terpene Terpene — — — — Amount Parts by  8 10 — — — — WeightOrganic Fibers (B) Amount Parts by — — 30 40 50 30 Weight Type — — — PET4 PET 4 PET 4 PET 4 Tensile Breakage % — — 15 15 15 15 ElongationThermoplastic Resin Type — — — PP PP PP PP (H) Amount Parts by — — 62 5038 62 Weight Compound (I) Type — — — Terpene Terpene Terpene TerpeneAmount Parts by — —  8 10 12  8 Weight

TABLE 2 Example 1 Example 2 Example 3 Example 4 Example 5 Raw CarbonFibers (A) Amount Parts by 20 20 20 20 20 Materials Weight FiberDiameter μm 7 7 7 7 7 [O/C] — 0.2 0.2 0.2 0.2 0.2 Organic Fibers (B)Amount Parts by 10 10 10 10 10 Weight Type Type PET 3 PET 4 PET 5 PET 6PET 5 Fiber Diameter μm 35 50 100 290 100 Tensile Breakage % 15 15 15 1515 Elongation Thermoplastic Resin Type — PP PP PP PP PP (C) Amount Partsby 70 70 70 70 70 Weight Compound (D) Type — Terpene Terpene TerpeneTerpene Terpene Amount Parts by 8 8 8 8 8 Weight Molding Average FiberLength L_(B) mm 7 7 7 7 7 Material Number Average Fiber d_(B) μm 35.150.1 101.0 290.0 101.0 Diameter Aspect Ratio L_(B)/d_(B) — 199 140 69 2369 Molded Average Fiber Length L_(A) mm 1.0 1.0 1.1 1.1 0.7 ArticleAverage Fiber Length L_(B) mm 3.0 2.9 3.0 3.0 2.8 Number Average Fiberd_(B) μm 35.1 50.1 101.0 290.0 101.0 Diameter Aspect Ratio L_(B)/d_(B) —85 58 30 10 28 Ratio of Calculated n_(B)/n_(A) — 0.009 0.004 0.0010.0001 0.0008 Number Evaluation Dispersibility — A A A A A ResultsCharpy Impact Strength kJ/m² 22.5 22.5 22.0 21.0 20.5 Flexural StrengthMPa 195 195 195 195 195 Surface Appearance — B B A B B

TABLE 3 Example 6 Example 7 Example 8 Example 9 Raw Carbon Fibers (A)Amount Parts by 30 20 20 20 Materials Weight Fiber Diameter μm 7 7 7 7[O/C] — 0.2 0.2 0.2 0.2 Organic Fibers (B) Amount Parts by 10 30 10 10Weight Type Type PET 4 PET 4 PET 4 PET 4 Fiber Diameter μm 50 50 50 50Tensile Breakage % 15 15 15 15 Elongation Thermoplastic Resin Type — PPPP PP PC (C) Amount Parts by 60 50 70 70 Weight Compound (D) Type —Terpene Terpene Terpene Terpene Amount Parts by 11 14 8 8 Weight MoldingAverage Fiber Length L_(B) mm 7 7 7 7 Material Number Average Fiberd_(B) μm 50.1 50.0 50.1 50.1 Diameter Aspect Ratio L_(B)/d_(B) — 140 140140 140 Molded Average Fiber Length L_(A) mm 0.9 1.0 1.1 1.2 ArticleAverage Fiber Length L_(B) mm 2.8 3.0 2.9 2.9 Number Average Fiber d_(B)μm 50.1 50.0 50.1 50.1 Diameter Aspect Ratio L_(B)/d_(B) — 56 60 58 58Ratio of Calculated n_(B)/n_(A) — 0.003 0.013 0.005 0.005 Number MoldingFiber Arrangement — Unevenly Unevenly Unevenly Unevenly Materialdistributed distributed distributed distributed Constitution Crosssection of (A) includes (B) — — — YES — Fiber Bundle (E) (B) includes(A) — — — — YES At least each one part of (A) — YES YES — — and (B)contacts to (C) Evaluation Dispersibility — A B B B Results CharpyImpact Strength kJ/m² 25.0 26.0 22.5 22.0 Flexural Strength MPa 240 180195 195 Surface Appearance — A B B B

TABLE 4 Example 10 Example 11 Example 12 Example 13 Molding Carbon FiberReinforced Thermoplastic Amount Parts by 67 17 — 67 Material ResinMolding Material (X-1) Weight Carbon Fiber Reinforced ThermoplasticAmount Parts by — — 75 — Resin Molding Material (X-2) WeightThermoplastic Resin (C) Type — — PP — — Amount Parts by — 8 — — WeightOrganic Fiber Reinforced Thermoplastic Amount Parts by 33 — — — ResinMolding Material (Y-1) Weight Pellet Length 7 mm Organic Fiber Type —PET 4 — — — Aspect Ratio L_(B)/d_(B) — 140 — — — Tensile Breakage % 15 —— — Elongation Organic Fiber Reinforced Thermoplastic Amount Parts by —75 25 — Resin Molding Material (Y-2) Weight Pellet Length 7 mm OrganicFiber Type — — PET 4 PET 4 — Aspect Ratio L_(B)/d_(B) — — 140 140 —Tensile Breakage % — 15 15 — Elongation Organic Fiber ReinforcedThermoplastic Amount Parts by — — — — Resin Molding Material (Y-3)Weight Pellet Length 7 mm Organic Fiber Type Type — — — — Aspect RatioL_(B)/d_(B) — — — — — Tensile Breakage % — — — — Elongation OrganicFiber Reinforced Thermoplastic Amount Parts by — — — 33 Resin MoldingMaterial (Y-4) Weight (Manufactured by melt-kneading) Organic Fiber TypeType — — — PET 4 PET 4 Average Fiber Length 2.5 mm Aspect RatioL_(B)/d_(B) — — — — 50 Tensile Breakage % — — — 15 Elongation MoldedAverage Fiber Length L_(A) mm 1.0 1.0 1.0 1.0 Article Average FiberLength L_(B) mm 3.0 2.9 2.9 1.8 Number Average Fiber Diameter d_(B) μm50.0 50.0 50.1 50.1 Aspect Ratio L_(B)/d_(B) — 60 58 58 36 Ratio ofCalculated Number n_(B)/n_(A) — 0.004 0.053 0.003 0.007 EvaluationProductivity — B B B A Results Dispersibility — A A B A Charpy ImpactStrength kJ/m² 22.5 25.0 23.0 21.0 Flexural Strength MPa 195 140 235 195Surface Appearance — A B B A

TABLE 5 Compar- Compar- Compar- Compar- Compar- Compar- Compar- ativeative ative ative ative ative ative Example 1 Example 2 Example 3Example 4 Example 5 Example 6 Example 7 Raw Carbon Fibers (A) AmountParts by 20 3 50 20 20 20 20 Materials Weight Fiber Diameter μm 7 7 7 77 7 7 [O/C] — 0.2 0.2 0.2 0.2 0.2 0.2 0.2 Organic Fibers (B) AmountParts by 10 10 10 50 10 10 10 Weight Type Type PET 2 PET 3 PET 3 PET 3PET 3 PET 3 PET 1 Fiber Diameter μm 20 35 35 35 35 35 12 TensileBreakage % 15 15 15 15 15 15 15 Elongation Thermoplastic Resin (C) Type— PP PP PP PP PP PP PP Amount Parts by 70 87 40 30 70 70 70 WeightCompound (D) Type — Terpene Terpene Terpene Terpene Terpene TerpeneTerpene Amount Parts by 8 6 14 16 8 8 8 Weight Molding Average FiberLength L_(B) mm 7 7 7 7 7 7 7 Material Number Average Fiber d_(B) μm20.1 35.0 35.1 35.0 35.0 35.1 12.1 Diameter Aspect Ratio L_(B)/d_(B) —897 200 199 200 200 199 579 Molded Average Fiber Length L_(A) mm 1.1 1.00.7 0.3 0.2 0.3 1.0 Article Average Fiber Length L_(B) mm 2.7 2.9 2.92.8 1.2 0.4 2.6 Number Average Fiber d_(B) μm 20.1 35.0 35.1 35.0 35.035.1 12.0 Diameter Aspect Ratio L_(B)/d_(B) — 134 83 83 80 34 11 217Ratio of Calculated n_(B)/n_(A) — 0.032 0.060 0.003 0.014 0.004 0.0190.085 Number Evaluation Dispersibility — A A C D A A A Results CharpyImpact Strength kJ/m² 23.0 9.5 10.0 11.0 13.0 11.5 23.5 FlexuralStrength MPa 193 95 275 105 155 165 190 Surface Appearance — C B D D B BC

TABLE 6 Comparative Comparative Comparative Example 8 Example 9 Example10 Raw Carbon Fibers (A) Amount Parts by 3 10 20 Materials Weight FiberDiameter μm 7 7 7 [O/C] — 0.2 0.2 0.2 Organic Fibers (B) Amount Parts by20 50 10 Weight Type Type PET 3 PET 3 PET 3 Fiber Diameter μm 35 35 35Tensile Breakage % 15 15 15 Elongation Thermoplastic Resin (C) Type — PPPP PP Amount Parts by 77 40 70 Weight Compound (D) Type — TerpeneTerpene Terpene Amount Parts by 8 16 8 Weight Molding Average FiberLength L_(B) mm 7 7 7 Material Number Average Fiber d_(B) μm 35.0 35.035.0 Diameter Aspect Ratio L_(B)/d_(B) — 200 200 200 Molded AverageFiber Length L_(A) mm 1.1 0.7 0.2 Article Average Fiber Length L_(B) mm3.0 2.7 2.5 Number Average Fiber d_(B) μm 35.0 35.0 35.0 Diameter AspectRatio L_(B)/d_(B) — 86 77 71 Ratio of Calculated n_(B)/n_(A) — 0.1280.068 0.002 Number Molding Fiber Arrangement — Unevenly Unevenly EvenlyMaterial distributed distributed distributed Constitution Cross sectionof Fiber (A) includes (B) — — — — Bundle (E) (B) includes (A) — — — — Atleast each one part of (A) — YES YES YES and (B) contacts to (C)Evaluation Dispersibility — A D D Results Charpy Impact Strength kJ/m²10.5 10.5 10.5 Flexural Strength MPa 95 95 155 Painted SurfaceAppearance — B C B

TABLE 7 Comparative Comparative Example 11 Example 12 Molding CarbonFiber Reinforced Thermoplastic Amount Parts by 67 10 Material ResinMolding Material (X-1) Weight Carbon Fiber Reinforced ThermoplasticAmount Parts by — — Resin Molding Material (X-2) Weight ThermoplasticResin (C) Type — PP PP Amount Parts by 33 70 Weight Organic FiberReinforced Thermoplastic Amount Parts by — — Resin Molding Material(Y-1) Weight Pellet Length 7 mm Organic Fiber Type — — — Aspect RatioL_(B)/d_(B) — — — Tensile Breakage % — — Elongation Organic FiberReinforced Thermoplastic Amount Parts by — — Resin Molding Material(Y-2) Weight Pellet Length 7 mm Organic Fiber Type — — — Aspect RatioL_(B)/d_(B) — — — Tensile Breakage % — — Elongation Organic FiberReinforced Thermoplastic Amount Parts by — 20 Resin Molding Material(Y-3) Weight Pellet Length 7 mm Organic Fiber Type Type — PET 4 AspectRatio L_(B)/d_(B) — — 140  Tensile Breakage % — 15 Elongation OrganicFiber Reinforced Thermoplastic Amount Parts by — — Resin MoldingMaterial (Y-4) Weight (Manufactured by melt-kneading) Organic Fiber TypeType — — PET2 Average Fiber Length 2.5 mm Aspect Ratio L_(B)/d_(B) — — —Tensile Breakage % — — Elongation Molded Average Fiber Length L_(A) mm  1.0   1.0 Article Average Fiber Length L_(B) mm —   2.9 Number AverageFiber Diameter d_(B) μm —   50.0 Aspect Ratio L_(B)/d_(B) — — 58 Ratioof Calculated Number n_(B)/n_(A) — —    0.029 Evaluation Productivity —B B Results Dispersibility — A A Charpy Impact Strength kJ/m²   9.0  10.0 Flexural Strength MPa 238  95 Painted Surface Appearance — A B

The materials prepared in Examples 1 to 13 were all excellent indispersibility of the carbon fibers (A) and the organic fibers (B), andexhibited high impact strength (Charpy impact strength) and good surfaceappearance.

On the other hand, in Comparative Examples 1 and 7, the small numberaverage fiber diameter of the organic fibers (B) resulted ininsufficient surface appearance. In Comparative Examples 2, 8, and 12,the decreased content of the carbon fibers (A) resulted in low impactstrength and low flexural strength. In Comparative Example 3, theincreased content of the carbon fibers (A) caused poor dispersion in themolded article, resulting in low impact strength and poor surfaceappearance. In Comparative Examples 4 and 9, the increased content ofthe organic fibers (B) led to increased entanglement between the organicfibers (B), poor dispersion and poor surface appearance, and occurrenceof fiber breakage due to increased contact between the fibers, therebyresulting in low impact strength. In Comparative Examples 5 and 6, theshort average fiber length of the carbon fibers (A) or the organicfibers (B) led to a smaller fiber reinforcing effect, resulting in lowimpact strength. In Comparative Example 10, a uniformly mixeddisposition of the carbon fibers (A) and the organic fibers (B) in aninternal cross section of the fiber bundle (E) in the molding materialled to increased entanglement between fibers in the fiber bundle (E), ashorter average fiber length of the carbon fibers (A), and unevendispersion in the molded article, thereby resulting in low impactstrength. In Comparative Example 11, the absence of the organic fibers(B) led to a smaller fiber reinforcing effect, resulting in low impactstrength.

INDUSTRIAL APPLICABILITY

The fiber reinforced thermoplastic resin molded article has an excellentfiber dispersibility and excellent mechanical properties, particularly,impact strength and surface appearance, and thus is suitably used forelectrical and electronic equipment, office automation equipment,household electrical appliances, housings, automotive parts and thelike.

The invention claimed is:
 1. A fiber reinforced thermoplastic resinmolded article comprising: 5 to 45 parts by weight of carbon fibers (A);1 to 45 parts by weight of organic fibers (B); and 10 to 94 parts byweight of a thermoplastic resin (C), based on 100 parts by weight of thetotal amount of the carbon fibers (A), the organic fibers (B), and thethermoplastic resin (C), wherein the carbon fibers (A) have an averagefiber length (L_(A)) of 0.3 to 3 mm, and the organic fibers (B) have anaverage fiber length (L_(B)) of 0.5 to 5 mm, and a number average fiberdiameter (d_(B)) of 35 to 300 μm.
 2. The fiber reinforced thermoplasticresin molded article according to claim 1, wherein the organic fibers(B) have an aspect ratio (L_(B) [μm]/d_(B) [μm]) of 5 to
 100. 3. Thefiber reinforced thermoplastic resin molded article according to claim1, wherein a ratio (n_(B)/n_(A)) of a calculated number n_(B) of theorganic fibers (B) to a calculated number n_(A) of the carbon fibers (A)is 0.001 to 0.01.
 4. The fiber reinforced thermoplastic resin moldedarticle according to claim 3, wherein the organic fibers (B) have anumber average fiber diameter (d_(B)) of 50 to 150 μm.
 5. The fiberreinforced thermoplastic resin molded article according to claim 3,wherein the organic fibers (B) are at least one selected from the groupconsisting of polyamide fibers, polyester fibers, polyarylene sulfidefibers, and fluorine fibers.
 6. A fiber reinforced thermoplastic resinmolding material comprising: 5 to 45 parts by weight of carbon fibers(A); 1 to 45 parts by weight of organic fibers (B); 10 to 94 parts byweight of a thermoplastic resin (C); and 1 to 25 parts by weight of acompound (D) having a melt viscosity at 200° C. that is lower than thatof the thermoplastic resin (C), based on 100 parts by weight of thetotal amount of the carbon fibers (A), the organic fibers (B), and thethermoplastic resin (C), wherein: the organic fibers (B) have a numberaverage fiber diameter (d_(B)) of 35 to 300 μm; the thermoplastic resin(C) is contained at an outer side of a composite (F) obtained byimpregnating a fiber bundle (E) comprising the carbon fibers (A) and theorganic fibers (B) with the compound (D); the carbon fibers (A) and theorganic fibers (B) are unevenly distributed in a cross section of thefiber bundle (E); and the length of the fiber bundle (E) and the lengthof the fiber reinforced thermoplastic resin molding material aresubstantially the same.
 7. A fiber reinforced thermoplastic resinmolding material comprising: a carbon fiber reinforced thermoplasticresin molding material (X) comprising 5 to 45 parts by weight of carbonfibers (A), 35 to 94 parts by weight of a thermoplastic resin (C), and 1to 25 parts by weight of a compound (D) having a melt viscosity at 200°C. that is lower than that of the thermoplastic resin (C), based on 100parts by weight of the total amount of the carbon fibers (A), thethermoplastic resin (C), and the compound (D) having a melt viscosity at200° C. that is lower than that of the thermoplastic resin (C), whereinthe thermoplastic resin (C) is contained at an outer side of a composite(G) obtained by impregnating the carbon fibers (A) with the compound(D), and the length of the carbon fibers (A) and the length of thecarbon fiber reinforced thermoplastic resin molding material aresubstantially the same; and an organic fiber reinforced thermoplasticresin molding material (Y) comprising 1 to 45 parts by weight of organicfibers (B), 35 to 94 parts by weight of a thermoplastic resin (H), and 1to 25 parts by weight of a compound (I) having a melt viscosity at 200°C. that is lower than that of the thermoplastic resin (H), based on 100parts by weight of the total amount of the organic fibers (B), thethermoplastic resin (H), and the compound (I), wherein the organicfibers (B) have a number average fiber diameter (d_(B)) of 35 to 300 μm.8. The fiber reinforced thermoplastic resin molding material accordingto claim 6, wherein the organic fibers (B) have an aspect ratio(L_(B)/d_(B)) of 10 to
 500. 9. The fiber reinforced thermoplastic resinmolding material according to claim 6, wherein the organic fibers (B)are at least one selected from the group consisting of polyamide fibers,polyester fibers, polyarylene sulfide fibers, and fluorine fibers. 10.The fiber reinforced thermoplastic resin molding material according toclaim 7, wherein the organic fibers (B) have an aspect ratio(L_(B)/d_(B)) of 10 to
 500. 11. The fiber reinforced thermoplastic resinmolding material according to claim 7, wherein the organic fibers (B)are at least one selected from the group consisting of polyamide fibers,polyester fibers, polyarylene sulfide fibers, and fluorine fibers.